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Biomedical subjects

M Kumar

Publications and source records attributed to M Kumar.

At least 271 records · Page 15Linked to original sources
PubMed1994

Monitoring intrathecal temperature: does core temperature reflect intrathecal temperature during aortic surgery?

Paraplegia secondary to spinal cord ischemia is a common occurrence following proximal aortic surgery. Recent research has suggested that modest reductions in neuronal temperature (ie, a 2 to 5 degrees C reduction) may protect the central nervous system from ischemic injury, and several medical centers are now using modest whole body hypothermia in an attempt to protect the spinal cord during aortic surgery. However, to date, there are no reports to validate that reductions in core temperature will reduce intrathecal temperature during aortic surgery. In the present study, the correlation between core temperature, assessed with a pulmonary artery thermistor, and intrathecal temperature, assessed with a lumbar intrathecal thermocouple, were evaluated. Both devices were corrected for bias using a mercury thermometer standard. It was found that there was excellent correlation between pulmonary artery temperature and intrathecal temperature during all portions of the surgery (r = 0.948; P < 0.001). The regression line for the relationship was defined by the formula: intrathecal temperature = 0.98 x pulmonary artery temperature + 0.65. Furthermore, there was excellent correlation between bias-corrected intrathecal temperature and the temperature measured by commercially available, bias-uncorrected thermistors placed in the esophagus (r = 0.869; P < or = 0.001), urinary bladder (r = 0.873; P < 0.001), and pulmonary artery (r = 0.929; P < 0.001). Based on these data, it is concluded that there is a close correlation between intrathecal temperature and core temperatures during proximal aortic surgery, and commercially available thermistors provide sufficient accuracy to assess spinal cord cooling during attempts to protect the spinal cord from ischemic injury.

Aortic Aneurysm, Abdominal↗
PubMed1994

Cerebrospinal fluid dopamine in HIV-1 infection.

BACKGROUND: Increasing evidence suggests significant involvement of the basal ganglia in patients with HIV-1 infection. OBJECTIVE: To study the effect of HIV-1 infection on cerebrospinal fluid (CSF) dopamine levels. DESIGN: CSF dopamine levels were measured by high-performance liquid chromatography. SETTING: A university-based outpatient clinic in south Florida involved in clinical AIDS research. SUBJECTS: Twenty-two subjects were enrolled in a prospective, longitudinal study of the neurological complications of AIDS. Five subjects were HIV-seronegative, but at risk for HIV-1 infection, 11 were HIV-1-seropositive without neurological disease and six had HIV-1-related neurological disease. RESULTS: The CSF dopamine mean values were significantly lower in the HIV-1-seropositive group with (P < 0.0001) or without (P < 0.0001) neurological disease than in the HIV-seronegative group. There was a very strong correlation between CD4 lymphocyte counts and CSF dopamine levels (P = 0.004) in the neurologically symptomatic group (P = 0.0008), but not in the other two groups. CONCLUSION: HIV-1 infection appears to have an effect on the central nervous system dopaminergic systems, as reflected in levels of CSF dopamine.

Adult↗
PubMed1994

A hypercellulolytic mutant of Fusarium oxysporum.

Multiple mutagenesis of Fusarium oxysporum DSM 841 resulted in enhanced yields of cellulases. The hypercellulolytic mutant (NTG-19) secretes high levels of extracellular cellulases on different cellulosic substrates. Addition of surfactant, Tween-80, further increased enzyme secretion by about 30%. The results on hydrolysis of wheat straw by parent strain, DSM 841 and mutant NTG-19 cellulases also revealed a significant improvement in the hydrolytic potential of the cellulolytic enzymes from the mutant NTG-19.

Cellulase↗
PubMed1994

Diagnostic and prognostic significance of lactate dehydrogenase in cerebrospinal fluid in patients of meningitis.

Activity of lactate dehydrogenase was measured in cerebrospinal fluid in 60 cases of meningitis (35 pyogenic, 18 tuberculous and 7 viral). Thirty age and sex matched healthy controls were taken to find out its diagnostic and prognostic significance in meningitis. The cerebrospinal fluid lactate dehydrogenase activity was significantly higher (p < 0.001) in cases of pyogenic meningitis and tuberculous meningitis as compared to the control group. The maximum elevation was seen on the 1st day in all types of meningitis but the activity declined significantly thereafter in patients of pyogenic meningitis who recovered without complications. However, in 2 cases of pyogenic meningitis and 5 cases of tuberculous meningitis who survived with complications, the lactate dehydrogenase activity on subsequent estimations increased serially. Further, the basal lactate dehydrogenase activity in 9 cases of pyogenic meningitis (who expired) was higher than those who survived without complications. The basal lactate dehydrogenase activity in pyogenic meningitis was significantly higher (p < 0.05) as compared to tuberculous meningitis and viral meningitis patients (p < 0.02) in this study.

Adolescent↗
PubMed1994

Electrophysiological studies (MNCV and H-RL) in twin babies.

Twenty-six fullterm and eight preterm babies born of twin pregnancies were studied. Offsprings were subjected to measurements of weight, crown heel length and head circumference along with motor nerve conduction velocity (MNCV) and H-reflex latency (H-RL) at right median nerve. The preterm twins had significantly lower MNCV and higher H-RL. The electrophysiological parameters did not vary in first and second born twins as well as in heavier and lighter twins. Three pairs of twins were available for follow-up study.

Birth Weight↗
PubMed1993

Bilateral Wilms tumor. Review of outcome, associated abnormalities, and late effects in 36 pediatric patients treated at a single institution.

BACKGROUND: Patients with bilateral Wilms tumor have an increased incidence of associated abnormalities and nephrogenic rests and require individualized multimodality therapy for cure. The authors reported the associated abnormalities, outcome, complications, and late effects of treatment in a group of children with bilateral Wilms tumor treated at St. Jude Children's Research Hospital, Memphis, Tennessee, over a 28-year period. METHODS: The records of 36 consecutive pediatric patients diagnosed with bilateral Wilms tumor between 1962-1990 were analyzed. Biopsy material was also reviewed, with particular emphasis on characterization of nephrogenic rests and histology. RESULTS: Twenty-nine patients had synchronous tumors and 7 had metachronous lesions. Associated physical abnormalities were present in 12 patients and involved the genitourinary, cardiovascular, integumentary, and musculoskeletal systems. The overall survival for patients with metachronous tumors (71%) was similar to that for those with synchronous tumors (70%). There was no effect of age or the presence of nephroblastomatosis. Two patients with synchronous tumors initially treated with nephrectomy eventually required bilateral nephrectomies for contralateral recurrence after chemotherapy and radiation therapy. Nephrogenic rests were present in 22 of 30 evaluable patients. Two of three patients with metachronous tumors had intralobar nephrogenic rests. Bilateral renal salvage procedures were demonstrated to be technically feasible and effective in controlling disease without compromising renal function or survival. Late effects included scoliosis in three patients treated before 1970, cardiomyopathy in one patient who received 300 mg/m2 doxorubicin and 12 Gy pulmonary irradiation, and benign tumors in two patients, one of whom also had a bowel obstruction. Serum creatinine, urea nitrogen, and blood pressure were normal in 23 of 26 survivors. CONCLUSIONS: The authors' experience supports a favorable outcome with minimal late effects for patients with bilateral Wilms tumor who receive individualized therapy at pediatric oncology centers.

Child↗
PubMed1993

The fidelity and dynamic response of fluid-filled catheter systems for direct measurement of lumbar cerebrospinal fluid pressure.

OBJECTIVE: The purpose of this study was to determine the fidelity of pressure signals transmitted through long, narrow (epidural) catheters inserted into the lumbar intrathecal space. METHODS: Using a model of the spinal canal we tested three epidural catheters: 20-gauge Arrow, 20-gauge Abbott, 21-gauge Portex. We (1) determined the damping coefficient and natural frequency of the three catheters, (2) correlated the static pressures measured using the three catheters compared to the true pressure in the intrathecal space, and (3) compared the response time of the three catheters connected to transducers vs U-tube manometers. RESULTS: The three catheters had high damping coefficients (alpha) (Arrow, 0.75; Abbott, 0.85; Portex, 1.10) and low natural frequencies (Arrow, 15.23 Hz; Abbott, 12.83 Hz; Portex, 9.09 Hz). The dynamic response characteristics of the catheter with the largest internal diameter (20-gauge Arrow) were adequate to reproduce pulsatile cerebrospinal fluid pressure reliably. Smaller catheters tracked the mean pressure, although oscillations were damped. Static pressure measurements from all three catheters showed good correlation with test pressures (r = 0.99; p < 0.001). Using the U-tube manometer, it required 170, 140, and 130 minutes for the Portex, Abbott, and Arrow catheters, respectively, to equilibrate with a test pressure of 30 cm H2O. The rate of rise in the U-tube manometer pressure was limited by the rate of fluid flow through the catheters. CONCLUSIONS: We found that a catheter of at least 20 gauge connected to a transducer could record pressures in the cerebrospinal fluid compartment with a high degree of fidelity. The prolonged time to reach equilibrium made U-tube manometry unsuitable for clinical use.

Catheterization↗
PubMed1993

Defensiveness, trait anxiety, and Epstein-Barr viral capsid antigen antibody titers in healthy college students.

The relationship of individual differences in repressive coping styles with differences in antibody titer to Epstein-Barr viral capsid antigen (EBV-VCA) were investigated in a normal, healthy college population made up of people previously exposed to EBV. Each of 54 1st-year undergraduates completed a battery of physical-status questions and items pertaining to potential behavioral immunomodulatory confounds, along with the Taylor Manifest Anxiety Scale (T-MAS) and the Marlowe-Crowne Social Desirability Scale (MC-SDS). Ss reporting high and middle levels of anxiety had higher antibody titers to EBV, suggesting poorer immune control over the latent virus, as compared with the low-anxious group. Similarly, high-defensive Ss had higher antibody titers than their low-defensive counterparts, and neither group differed from the middle group.

Adolescent↗
PubMed1993

Abnormal pituitary-adrenocortical response in early HIV-1 infection.

The corticotropin-adrenocortical response to cold pressor challenge was investigated in a study of human immunodeficiency virus (HIV) infection. Data obtained from 16 HIV-1-positive and 28 HIV-1-negative subjects are presented in this report. After the insertion of a venicatheter and following 30 min of rest, the subjects immersed one of their hands in an ice-water mixture for 2 min, and serial blood samples were obtained for the determination of ACTH and cortisol levels. The results show a significant blunting in the ACTH response and marginally lower levels of cortisol, over all time points, in HIV-1-positive subjects compared to that in HIV-1-negative subjects.

Adrenocorticotropic Hormone↗
PubMed1993

Evaluation of amphotericin B as a first line drug in comparison to sodium stibogluconate in the treatment of fresh cases of kala-azar.

A total of 150 patients of kala-azar matched for age and sex and parasitologically proved were randomly allocated to two equal treatment groups. Patients in one group received amphotericin B(AMB) in a dose of 1 mg/kg body weight (BW) on alternate days starting with 0.05 mg/kg/bw on first day with daily increments, till a total dose of 20 mg/kg/bw was given; the patients in the second group received sodium stibogluconate (SAG) in the dose of 20 mg/kg/bw, im daily for 30 days. The efficacy, safety and cost-effectiveness of the two drugs were compared. Apparent cure (afebrile at the end of therapy) in 75 (100%) and 69 (92%) patients and ultimate cure (no relapse in six months of follow up) in 75 (100%) and 60 (80%) patients occurred in the AMB and SAG groups respectively. The difference between the ultimate cure in the two groups was significant (P < 0.001). Six (8%) and 9(12%) patients of SAG group showed primary (with no response to SAG during treatment) and secondary unresponsiveness (with no response to SAG after relapse) respectively and they were cured with amphotericin B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Molecular genetic, cytogenetic, and immunohistochemical characterization of alveolar soft-part sarcoma. Implications for cell of origin.

BACKGROUND: Alveolar soft-part sarcoma is a rare tumor of uncertain histogenesis. METHODS: The authors report a patient who was studied using immunohistochemistry, cytogenetic analysis, and molecular probes for MyoD1 and MYCN (N-myc proto-oncogene). RESULTS: By immunoperoxidase, the tumor was focally positive for vimentin, neuron-specific enolase, and S-100 protein but negative for muscle-specific actin, desmin, and low-molecular-weight keratin. Direct chromosome analysis of primary tumor cells using G-banded preparations yielded two clonally abnormal lines: one demonstrated trisomy 47,XX+5; the other demonstrated 46,XX,1p-,17q+. Expression of the MYCN RNA was detectable at a low level, and MYCN was single copy at the DNA level. Expression of the myogenic molecular marker MyoD1 was not detected by Northern blotting analysis. CONCLUSIONS: This is the first detailed study to address the molecular biology and tumor cytogenetics of alveolar soft-part sarcoma. The results of this study indicate a neurogenic origin for this unusual tumor and fail to provide support for the notion of a myogenic origin.

Adolescent↗
PubMed1992

Phenytoin as a coanalgesic in cancer pain.

The efficacy of phenytoin (PHT), buprenorphine (Bu), and Bu+PHT for the relief of cancer pain of various etiologies was evaluated in a randomized, double-blind study of 3 groups, each comprised of 25 patients. Treatment duration was 1 month. PHT (100 mg by mouth twice daily) provided greater than 50% pain relief to 18 patients (72%) and greater than 75% relief to 4 (16%). Bu (0.2 mg sublingually twice daily) gave 21 patients (84%) greater than 50% relief and 15 patients (60%) greater than 75% relief. Of the Bu-treated patients, 8 had major side effects, while none of the PHT-treated patients experienced significant untoward reactions. Combined therapy (PHT, 50 mg PO+Bu 0.1 mg SL twice daily) provided greater than 50% pain relief to 22 patients (88%) and greater than 75% to 18 (72%); only 3 patients experienced a significant side effect. This study suggests that phenytoin has mild-to-moderate pain-relieving properties of its own and can significantly enhance buprenorphine analgesia. By permitting a lower opioid dose, it may reduce the occurrence of opioid-related side effects. PHT's lack of serious side effects, as well as its documented anxiolytic and antidepressant actions, may add to its comparative usefulness. Further clinical trials of PHT as a coanalgesic and/or adjuvant agent in cancer pain are warranted.

Adult↗