CONTEXT The subject of economic migration among health care professionals has received intense attention. However, the aetiology of this migration has not been rigorously evaluated in Pakistan. Such knowledge can potentially influence health care and academic policies. Our current study proposes to quantify the relative contributions of various personal, professional and economic variables among final-year medical students in Karachi.METHODS A self-administered structured questionnaire using a 10-point scale was developed and piloted among Karachi medical students. Additional openended questions were included to allow us to capture information not otherwise covered in the questionnaire. SPSS software was used for data entry and analysis.RESULTS Over 95% of Aga Khan University (AKU) and over 65% of Baqai University (BU) final-year medical students intend to proceed abroad for their postgraduate training. The 2 most important factors behind this intent as pointed out by the students are poor salary structure (AKU mean score 8.94 ± 1.73, BU mean score 7.14 ± 2.6) and poor quality of training in the home country (AKU mean score 9.20 ± 1.20, BU mean score 8.68 ± 2.03). Other interesting factors captured through the open-ended questions were the poor work environment and lack of rigor in teaching of residents in domestic university hospitals. Over 50% of final-year medical students cited these issues as major reasons behind their decision to migrate.

We report our long-term experience using enteral levodopa infusions in 22 patients with Parkinson's disease and severe motor fluctuations. Amelioration of intractable dyskinesias was the most important factor that determined whether patients chose to continue using the infusion pump system. Mechanical and physical problems associated with enteral access were the most common reasons for which patients discontinued pump use. Nearly all patients continued to have dramatically increased on time for the duration of follow up, suggesting that technically less-cumbersome systems that provide continuous dopaminergic stimulation are worthwhile and should be developed.

Muscle stiffness in stiff-person syndrome (SPS) is produced by continuous, involuntary firing of motor units that is thought to be caused by an autoimmune mediated dysfunction of GABA-ergic inhibitory neurones. We have postulated that the loss of GABA-ergic inputs from spinal interneurones alone is insufficient to produce tonic firing of motor neurones and that excessive supraspinal excitation could also play a role. To determine whether SPS is associated with dysfunction in supraspinal GABA-ergic neurones, we assessed the excitability of the motor cortex with transcranial magnetic stimulation (TMS) in seven SPS patients and seven age-matched healthy volunteers. SPS patients had normal central motor conduction times, normal thresholds for motor evoked potentials (MEPs) in leg muscles, and a normal MEP stimulus versus response recruitment curve with increasing TMS intensities in resting hand and leg muscles. Cortical silent periods were shortened in leg muscles. Intracortical inhibition and excitation were assessed while recording from the abductor pollicis brevis, using a paired pulse TMS paradigm with subthreshold conditioning stimuli. Patients had decreased inhibition and markedly increased facilitation at short intervals. Using paired suprathreshold TMS, patients exhibited increased facilitation at 20- and 40-ms intervals. These results point to a hyperexcitability of the motor cortex in SPS, which could be explained by impairment of supraspinal GABA-ergic neurones, leading to an impaired balance between inhibitory and excitatory intracortical circuitry.

We prospectively evaluated thalidomide-induced neuropathy using electrodiagnostic studies. Sixty-seven men with metastatic androgen-independent prostate cancer in an open-label trial of oral thalidomide underwent neurologic examinations and nerve conduction studies (NCS) prior to and at 3-month intervals during treatment. NCS included recording of sensory nerve action potentials (SNAPs) from median, radial, ulnar, and sural nerves. SNAP amplitudes for each nerve were expressed as the percentage of its baseline, and the mean of the four was termed the SNAP index. A 40% decline in the SNAP index was considered clinically significant. Thalidomide was discontinued in 55 patients for lack of therapeutic response. Of 67 patients initially enrolled, 24 remained on thalidomide for 3 months, 8 remained at 6 months, and 3 remained at 9 months. Six patients developed neuropathy. Clinical symptoms and a decline in the SNAP index occurred concurrently. Older age and cumulative dose were possible contributing factors. Neuropathy may thus be a common complication of thalidomide in older patients. The SNAP index can be used to monitor peripheral neuropathy, but not for early detection.

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