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Biomedical subjects

B Lynch

Publications and source records attributed to B Lynch.

At least 37 records · Page 2Linked to original sources
PubMed1990

Late hydrocephalus after arrest and resolution of neonatal post-hemorrhagic hydrocephalus.

This report describes the occurrence of rapid progression of hydrocephalus after discharge from the nursery in four of 48 infants who had had previous arrest of progression of post-hemorrhagic hydrocephalus, and at least partial resolution of ventriculomegaly. This later-onset hydrocephalus occurred at a mean age of seven months; the most consistent presenting clinical feature was rapid head growth. Three of the four infants required a ventriculo-peritoneal shunt and the fourth was treated with acetazolamide, with apparent resolution of the hydrocephalus. Newborn infants with post-hemorrhagic hydrocephalus should be followed carefully throughout the first year for prompt detection of later hydrocephalus.

Cephalometry↗
PubMed1988

Biological properties of two models of calcitonin gene related peptide with idealized amphiphilic alpha-helices of different lengths.

Previous studies on calcitonin gene related peptide (CGRP) have demonstrated that it has the characteristics of an amphiphilic peptide, and from an examination of the sequence, we have proposed that it contains an amphiphilic alpha-helix. We have synthesized two analogues of CGRP which have different lengths of idealized amphiphilic alpha-helical secondary structure. The first model, CGRM-1, has been substituted with residues generating an idealized amphiphilic alpha-helix in the region between residues 8 and 25, equivalent to approximately five turns of an alpha-helix. This peptide is not an agonist in any of our bioassays, but it does bind with low affinity to rCGRP receptors in crude liver membranes. Our second model, CGRM-2, has an idealized amphiphilic alpha-helix between residues 8 and 18, which is equivalent to approximately three turns of an alpha-helix. In an in vitro rat vas deferens assay, this peptide is an agonist with a potency one-fourth that of the native hormone. However, the potency of CGRM-2 in an adenylate cyclase assay is much lower, only 1/140th the potency of CGRP. Both model peptides display amphiphilic characteristics commensurate with their design. We conclude that there is an amphiphilic alpha-helix in rCGRP between residues 8 and 18 and that this helix terminates in the vicinity of residue 18.

Adenylyl Cyclases↗
PubMed1987

Biological and physical properties of a model calcitonin containing a glutamate residue interrupting the hydrophobic face of the idealized amphiphilic alpha-helical region.

2A new calcitonin analogue, model calcitonin III (MCt-III), has been synthesized, and its biological and physical characteristics have been studied. This analogue has an idealized alpha-helix from residue 8-22 with glutamate at position 15 interrupting an otherwise continuous surface of aliphatic side chains (those of leucine residues) on the hydrophobic face of the helix. MCt-III differs from a previous model, MCt-II, only by the substitution Leu15----Glu and is here compared with salmon calcitonin I (sCt-I) and MCt-II to elucidate further the role of the putative amphiphilic alpha-helix in determining biological and physical properties of the hormone. MCt-III shows physical properties intermediate between those of sCt-I and MCt-II, demonstrating the influence of appropriately positioned single residues on properties of amphiphilic structures. In our two biological assays, a brain-binding assay and an in vivo hypocalcemic assay, MCt-III reproduces the sigmoidal dose-response curves of sCt-I; this contrasts with the behavior of MCt-II, which demonstrated unusual dose-response curves in these two assays. MCt-III is almost three times more potent than sCt-I in our hypocalcemic assay; this activity groups MCt-III among the most potent known analogues of sCt-I.

Animals↗
PubMedDate not supplied

Complications common to ventricular assist device support are rare with 90 days of DeBakey VAD support in calves.

The DeBakey VAD is a miniaturized, electromagnetically driven axial flow pump intended for long-term ventricular assist. Safety and performance data from six calves implanted with the complete DeBakey VAD system are reported elsewhere; here we describe complications and necropsy findings for these same six animals, all of which survived 90 days. The study was conducted according to a uniform protocol, which included anticoagulation and antibiotic prophylaxis. Clinical complications tracked included bleeding, cardiovascular abnormalities (e.g., arrhythmias, tachycardia unrelated to pain, bradycardia), hemolysis, hepatic dysfunction, renal dysfunction, thromboembolism (neurologic or peripheral), or infection. Each adverse event was retrospectively categorized with regard to severity (mild, moderate, severe) and relationship to device. Clinical findings were confirmed by necropsy. There was no evidence of systemic infection, thromboembolism, hemolysis, or renal or hepatic dysfunction in these six animals during the study period. A single adverse event was noted in each of two of the calves. Both events were considered mild according to the predefined criteria. Bleeding related to the surgical implantation procedure and requiring reoperation occurred in one animal. The other animal had evidence of a superficial infection at the exit site of the cables on the left lateral thoracic wall; the infection did not extend into the thoracic cavity. Chronic, healed small renal infarct scars were present in several animals. Mild valvular endocardiosis was observed in two calves and mild fibroelastosis was present in the endocardium at the site of the inflow cannula in three calves; however, these lesions were not considered clinically significant. No other gross or histologic abnormalities were noted at necropsy. In conclusion, calves implanted with the complete DeBakey VAD for 90 days demonstrated few complications and had no significant necropsy findings. Complications common to ventricular assist device (VAD) support (i.e., hemolysis, infection, bleeding, thromboembolism) were rare during long-term support (90 days) with the DeBakey VAD.

Animals↗
PubMedDate not supplied

Foot deformities in children with hereditary motor and sensory neuropathy.

The authors reviewed 104 feet from 52 consecutive children with hereditary motor and sensory neuropathy (HMSN) seen for the first time in clinics in two pediatric institutions between 1996 and 2003. Sixty-nine feet had a cavovarus deformity, 23 feet had a planovalgus deformity, and 12 feet had no significant deformity. All cases with deformity had bilateral involvement, and of those with deformity, only 45% had symmetric involvement. In HMSN I, III, IV, V, and X-linked HMSN, cavovarus was the most common deformity. However, in HMSN II, 55% of feet had a planovalgus deformity, 36% had a cavovarus deformity, and 9% had no deformity. In all, 43 feet underwent surgery of some type. Surgery, and in particularly combined bony and soft tissue procedures, was performed much more frequently on feet with cavovarus than planovalgus deformities. Soft tissue surgery alone was performed at an earlier age than combined bony and soft tissue surgery.

Adolescent↗
PubMedDate not supplied

Relationship of carbamazepine reduction rate to seizure frequency during inpatient telemetry.

To establish guidelines for medication reduction during inpatient telemetry, the records of 18 children and young adults with refractory partial seizures undergoing carbamazepine (CBZ) reductions during continuous video/EEG telemetry were reviewed. Six patients were receiving CBZ monotherapy, and 12 patients were treated with an additional antiepileptic drug (AED) maintained at baseline dosage during CBZ taper. Despite relatively rapid mean reductions in dosage of 44% by day 2 of taper, no patients experienced frequent repetitive seizures or status epilepticus (SE). Seizure rate during the entire CBZ reduction period correlated significantly with rate of drug reduction. Linear regression analysis showed drug reduction rate to be a good predictor of seizure rate. Fourteen patients experienced at least three seizures during CBZ taper. On the average, the third seizure occurred on day 5 of taper at a percentage of dose reduction of 79%. In 8 patients, CBZ concentrations were measured both before taper and < or = 24 h after the third seizure. For these patients, seizure rate also correlated significantly with reduction in CBZ level. We conclude that manipulation of CBZ dose reduction rate is important in maximizing seizure frequency during telemetry and, in our patients, a relatively rapid rate of dose reduction was safe and effective in promoting seizure recordings.

Adolescent↗
PubMedDate not supplied

A collaborative program for international education.

A collaborative educational program for Japanese nurses was developed, which merged the resources of the practice and education settings at the Massachusetts General Hospital (MGH) and the MGH Institute of Health Professions. Two concurrent programs were developed--Adult Health and Maternal-Child Health. These concurrent programs focused on content reflecting key areas in the realm of nursing practice and education in both Japan and the United States. Complementary clinical tours were an integral part of the program. This dyad of lecture and clinical experiences provided a forum to focus on issues relevant to nursing worldwide.

Humans↗
PubMedDate not supplied

Climatic conditions and the reporting of sun-protective behavior survey data: a brief report.

Two hundred thirty-one spectators at a Cricket match in Brisbane, Australia, were interviewed and observed to determine their sun protective behaviors, and these behaviors were compared to the temperature and amount of cloud cover at the time of the study. People tended to protect themselves from the sun when there was less cloud cover and temperatures were higher.

Cross-Sectional Studies↗