Biomedical subjects
Publications and source records attributed to R Kulkarni.
A wide spectrum of complications is associated with invasive hemodynamic monitoring. We report an unusual case of perforation of the left internal mammary artery that occurred during percutaneous insertion of a Swan-Ganz catheter using the subclavian vein approach. To the best of our knowledge, this complication has not been previously reported.
OBJECTIVES: This study examined the effect of endocardial and transthoracic direct current (DC) shocks on left atrial and left atrial appendage function in humans with structural heart disease. BACKGROUND: DC cardioversion of atrial fibrillation (AF) to sinus rhythm is associated with transient left atrial and left atrial appendage dysfunction and the development of spontaneous echo contrast (SEC). This phenomenon has been termed atrial "stunning" and may be associated with thrombus formation and embolic stroke. To what extent the shock itself contributes to atrial stunning is unclear. METHODS: Thirteen patients in sinus rhythm undergoing implantation of a ventricular implantable cardioverter defibrillator (ICD) were prospectively evaluated. All patients had significant structural heart disease. To evaluate the effects of DC shocks on left atrial and left atrial appendage function, biphasic R wave synchronized endocardial shocks of 1, 10 and 20 J were delivered between the right ventricular electrode and the left pectoral generator of the ICD in sinus rhythm. R wave synchronized transthoracic shocks of 360 J were also delivered between anteriorly and posteriorly positioned chest electrodes. Transesophageal echocardiography was performed to evaluate left atrial appendage velocities, mitral inflow velocities and the presence of SEC before and immediately after each DC shock. RESULTS: There were no significant changes in left atrial or left atrial appendage function after endocardial or transthoracic DC shocks. Left atrial SEC did not develop after endocardial or transthoracic DC shocks. CONCLUSIONS: Endocardial and transthoracic DC shocks are not directly responsible for left atrial and left atrial appendage stunning and do not contribute to the stunning that is observed after the cardioversion of AF to sinus rhythm.
Astroblastoma is a rare and controversial tumor about which little is known. We have made the diagnosis in seven patients since 1990 at Memorial Sloan-Kettering Cancer Center. Four patients had astroblastomas with anaplastic features, whereas three patients had tumors which were well-differentiated. All three patients with low grade lesions are alive and recurrence free after surgery alone (mean follow-up 29 months). All four patients with anaplastic astroblastoma were treated with surgery, radiotherapy and chemotherapy. One died of infection during induction chemotherapy. Two others died of tumor progression at 28 and 42 months. Radiographic response to chemotherapy was seen in one patient. The results of our series and other reports suggest that anaplastic histology is a prognostic factor in the setting of astroblastoma. More aggressive treatment is necessary for patients with anaplastic astroblastoma although the precise role of irradiation and chemotherapy cannot be defined at this time.
The excitability of the lateral giant escape reflex of socially dominant and submissive crayfish at rest and during agonistic encounters was studied and compared. During agonistic encounters the excitability of the lateral giant reflex falls, substantially in subordinates and slightly in dominants, whereas at rest excitability seems to be independent of social status. Thus, paradoxically, socially dominant animals are more likely to execute lateral giant escape reactions during interactions than are subordinates. It is suggested that subordinates under threat of attack tend to engage circuitry involved in flexible, nonreflex ("voluntary") types of escape not mediated by giant neurons and therefore inhibit giant neuron-mediated reflex circuitry that produces prompt, but less adaptive, responses. In contrast, dominants go about their business, mainly ignoring their conspecifics and relying on reflex escape to protect them from unexpected attack. Consistent with this view, escape of subordinates during agonistic encounters is mediated by nongiant, not reflex, circuitry. These observations and their interpretation suggest a possible functional role for recently described social status-dependent serotonergic modulation of the lateral giant reflex, which is inhibitory in sign in subordinates and facilitatory in dominants.
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OBJECTIVE: To evaluate the role of percutaneous transluminal coronary angioplasty (PTCA) in the treatment of patients with unstable angina. DESIGN: Retrospective analysis of administrative records of all acute care hospital discharges at Robert Wood Johnson University Hospital from 1987 to 1993 with International Classification of Diseases, 9th revision, codes for coronary angioplasty and corresponding catheterization laboratory reports. SETTING: Tertiary care teaching hospital. RESULTS: Of 4826 PTCA cases, unstable angina was identified in 780 as the main indication for the procedure. Baseline clinical features of patients with unstable angina were not different from those in patients with stable angina. The overall success rate for PTCA in patients with unstable angina was significantly higher (707 of 780, 91%) than the success rate in patients with stable angina (3466 of 4046, 86%). The major complication rate in unstable angina patients was low (29 of 780, 3.7%) and did not differ from that in stable angina patients (136 of 4046, 3.4%). The success and complication rates in patients with unstable angina were analyzed in terms of time of PTCA, ie, early (less than 48 h from admission) versus late (48 h or more from admission). The procedure was successful in 343 of 380 (90%) patients treated early and 364 of 400 (91%) patients treated late (not significant), and the complication rates were low (12 of 380, 3.2% versus 17 of 400, 4.3%; not significant in both groups). However, length of hospital stay was considerably shorter for patients treated early than for patients treated late (4.5 +/- 3.3 days versus 10.4 +/- 6.6 days, respectively, P < 0.0001). CONCLUSION: Contemporary results of PTCA in patients with unstable angina parallel those reported for stable angina. Thus, PTCA appears to be an effective and safe treatment for unstable angina patients, and treating these patients soon after admission does not appear to affect the success or complication rates.
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There has been considerable controversy over whether general anesthetics act directly on membrane proteins, and if so, whether there are uniquely sensitive protein targets upon which they act. Here, we examine the actions of halothane on a diverse collection of voltage-gated potassium channels expressed in Xenopus oocytes, and find that they are all sensitive at clinically relevant concentrations. To investigate further the molecular basis of this commonality, human and rat minimal potassium (minK) channels, which have exceedingly short amino acid sequences, were examined. Current through these channels is reversibly reduced to 68% of control values by 0.5% (0.34 mM) halothane. A double deletion mutant of the 130-amino acid minK protein, in which 30 amino acids of the N-terminus, thought to be extracellular, and 37 amino acids of the putative intracellular C-terminus are deleted (resulting in a protein in which more than half of both the extracellular and intracellular domains have been removed) responds to low halothane concentrations similarly to the parent channel. While alternative explanations are possible, this result is consistent with a model whereby halothane interacts with the channel protein from within the lipid bilayer.
Forty-one patients with hemophilia A were studied for the prevalence of serological markers for hepatitis A, hepatitis B, hepatitis C (non-A and non-B hepatitis), and delta hepatitis (hepatitis D). Ten of 41 (24.4%) patients demonstrated hepatitis A antibody and 31 of 41 (75.6%) patients had a serologic marker for previous hepatitis B infection; four of these 31 patients (13%) also demonstrated antibody to delta agent (hepatitis D). Thirty-seven of 41 (90.2%) patients demonstrated antibody for hepatitis C. Nine of 31 (29%) patients with a hepatitis B marker (no hepatitis B vaccinees) were negative for anti-HBc but positive for anti-HBs; all of these nine patients were HIV antibody positive, although they had no overt immunodeficiency. Twenty-six of 41 (63.5%) patients were HIV antibody positive. Of HIV antibody positive patients, 27%, 88%, and 100% demonstrated evidence of a previous hepatitis A, hepatitis B, or hepatitis C, respectively. Of HIV antibody negative patients; 20%, 53%, and 73% of the patients demonstrated evidence of a previous hepatitis A, hepatitis B, or hepatitis C infections, respectively. The difference between HIV antibody positive and HIV antibody negative groups was not significant for hepatitis A but was significant for hepatitis B (P < 0.001) and hepatitis C (P < .001). Of the 31 patients with a hepatitis B serologic marker, all had antibody to hepatitis C. Of 10 patients, without a hepatitis B serologic marker, only 6 (60%) had antibody to hepatitis C.(ABSTRACT TRUNCATED AT 250 WORDS)
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A software package that allows one to carry out multiple alignment of protein and nucleic acid sequences of almost unlimited length and number of sequences is developed on C-DAC parallel computer--a transputer-based machine. The farming approach is used for data parallelization. The speed gains are almost linear when the number of transputers is increased from 4 to 64. The software is used to carry out multiple alignment of 100 sequences each of alpha-chain and beta-chain of hemoglobin and 83 cytochrome c sequences. The signature sequence of cytochrome c was found to be PGTKMXF. The single parameter, multiple alignment score, S, has been used to categorize proteins in different subfamilies and groups.
Evaluated the psychosocial adaptations of adolescents with cancer who were primarily off treatment (n = 19, ages 11-18) as compared with matched classroom controls in a 2-year longitudinal study on indices of (a) teacher, peer, and self-perceptions of social reputation; (b) multiple measures of popularity and friendships; and (c) self-reported feelings of loneliness, depression, and self-concept. Adolescents with cancer continued to have a social reputation as being more socially isolated, but no significant differences were identified on multiple measures of social acceptance or the self-reported feelings. In general, adolescents with cancer were similar to peers on numerous dimensions of psychological functioning manifesting minimal discernable psychosocial late effects.
A new case of X chromosome-linked phosphoglycerate kinase (PGK) abnormality is described. The male proband was mentally retarded, had behavior disorders, and displayed episodes of hemolytic anemia. The enzyme activity of red blood cells from the patient was about 10% of normal, and that of the cultured fibroblasts was about 50% of normal cells. The variant PGK was characterized by a lower affinity for the substrates, reduced thermostability, and increased anodal electrophoretic mobility. The pH activity profile of the variant enzyme was different from that of normal. The amount of messenger RNA (mRNA) in the variant fibroblasts was comparable to that of normal fibroblasts. The mRNA coding for PGK was subjected to coupled reverse transcription followed by amplification by the polymerase chain reaction. Nucleotide sequence of the variant cDNA showed a point mutation, T/A----C/G transition, in exon 9 of the variant gene. No other mutation was found in all coding regions of the variant. The mutation should cause Cys----Arg substitution at the 315th position from the NH2-terminal Ser of PGK, and it created an additional Ava II (or isoschimatic) cleavage site in the variant gene. Because the variant gene was not detected in the proband's mother and siblings, it must have been generated by spontaneous mutation during oogenesis.
Wolman's disease is a fatal disorder characterized by absence of acid lipase and accumulation of cholesterol esters. Inanition due to malabsorption and intractable diarrhea has been the most prominent cause of early demise within the first year. Further complications have included cirrhosis and pulmonary failure due to cholesterol ester storage in respective cells. Although sustained caloric balance can be maintained by total parenteral nutrition, this has not altered the eventual course of disease. The acid lipase deficiency in leucocytes in Wolman's disease can be corrected subsequent to bone marrow transplantation. This has proven to be the case in two patients so transplanted. In two other patients, engraftment was not obtained following bone marrow transplantation. The concept of treatment of Wolman's disease by providing normalization of the acid lipase activity by allogeneic bone marrow transplantation remains valid. However, improvement of bone marrow transplant procedure needs to be implemented since pre-existing morbid pathology enhances toxicity and may prevent engraftment. Alternative modifications for accomplishing sustained engraftment without toxicity need to be examined. Other potential therapies need to be inspected in treatment of patients with Wolman's disease. The capability of reducing cellular cholesterol synthesis by use of lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase, is now available. In the future, isolation and purification of acid lipase will allow for direct infusion of missing enzyme. The molecular biology now known concerning acid lipase gene holds promise for the future for recombinant manufacturing of acid lipase. And, gene therapy with its use of autologous bone marrow transplantation will be tried in future.(ABSTRACT TRUNCATED AT 250 WORDS)
Obtained self-reports of parenting practices from fathers and mothers of 24 children with cancer, and 24 controls using the Child-Rearing Practices Report (CRPR). Cancer patients were primarily in long-term remission and represented a typical pattern of childhood malignancies. Same age/sex controls were recruited from the classrooms of the children with cancer. In addition, CRPR ratings were obtained from experts in pediatric oncology based upon their prediction of how a parent of a child with cancer would respond. The experts predicted differences in the areas of overinvolvement, discipline, worry about the child, nutritional concerns, and use of supernatural explanations. Results from parents showed surprising similarity between the parents of children with cancer and control parents, and disagreement with the experts. Discussion focuses on explanations for this apparent contradiction.
Evaluated the psychosocial adaptations of children with cancer (n = 24, ages 8-18) as compared with same classroom controls on indices of (a) peer- and self-perceptions of sociability, aggression, and social isolation; (b) overall popularity; (c) mutual friendships; (d) feelings of loneliness; and (e) self-concept in multiple domains. Although the peer report data showed that children with cancer had a social reputation as significantly more socially isolated, no significant differences were found for their popularity, number of mutual friends, loneliness, or self-worth. Findings suggest that children with cancer have a reputation as more socially isolated, but differences were not found on measures of acceptance by peers, self-concept, or loneliness.