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Biomedical subjects

J Smith

Publications and source records attributed to J Smith.

At least 1,027 records · Page 57Linked to original sources
PubMed1987

Atresia of the esophagus. New trends in the management of high-risk neonates.

Once the reconstruction of esophageal atresia in infancy was reported, immediate repair became standard practice. High-risk infants carry an operative mortality of 30% to 80%. Staged surgical procedures were introduced to improve survival. "Delayed" reconstruction of esophageal atresia in selected cases has been reported to improve survival and eliminate staged surgical procedures. Between 1982 and 1986, 21 newborns were diagnosed as having esophageal atresia. Eight infants (32%) underwent "immediate" repair. In 13 infants repair was "delayed" for seven to 252 days. Four neonates with "pure" esophageal atresia underwent primary anastomosis, one was awaiting surgery, and another died in the postnatal period. As more high-risk infants survive the perinatal period, surgical reconstruction must be planned to maximize operative survival. The goal of delayed management of esophageal atresia is to restore intrinsic esophageal continuity.

Abnormalities, Multiple↗
PubMed1987

Sacrococcygeal chordoma. A clinicoradiological study of 60 patients.

Sixty patients with sacrococcygeal chordoma, who were seen at this center between 1946 and 1985, were studied with particular attention to the radiographic findings. This study was undertaken because of the large number of these cases and comparison was made between the plain films available in 39 patients and the computed tomography CT studies in 22. Bone destruction was found in 78% on plain films but in 90% on CT. A soft tissue mass was identified in plain films in 60% but in 90% on CT. Calcific debris was found in plain films in 44% but in 87% on CT. Mostly the debris consisted of coarse irregular fragments and probably represented sequestrated necrotic bone. Myelography was performed in only 15 patients. Angiography was studied in 10 cases. Of the 60 patients 88% underwent surgical resection. The tumor recurred in 80% and in only 20% was there no evidence of recurrence. Distant metastases occurred in 24% of patients. Fifty percent survived 5 years; 28% survived 10 years; mean survival 7.5 years.

Adult↗
PubMed1987

Postradiation sarcoma of bone in Hodgkin disease.

We report 16 cases seen in the Memorial Sloan-Kettering Cancer Center (MSKCC) during the past 50 years. These patients had been treated with external radiation for Hodgkin disease and had developed sarcomas in the field 4-31 years after the diagnosis of Hodgkin disease. Most of the tumors (12 of 16) occurred in the chest wall. There were three tumors of the pelvis and an unusual osteosarcoma of the femur following treatment for a primary Hodgkin disease of the femur. The tumors were predominantly osteosarcomas (9). In addition, there were five malignant fibrous histiocytomas, one fibrosarcoma, and one chondrosarcoma. Prognosis was poor; the mean survival was 12 months. Survival of patients with other primary cancers who developed radiation sarcomas was not significantly different from that of patients with Hodgkin disease. Hodgkin disease is now the most common tumor among radiation-induced sarcomas in previously normal bone and has surpassed breast cancer, which was previously the most common original tumor.

Adolescent↗
PubMed1987

Use of a modified Swan-Ganz pacing catheter for measuring Pdi and diaphragmatic EMG.

Measurements of pressures across the diaphragm (Pdi) and diaphragmatic electromyogram (EMG) have become an integral tool to study respiratory muscle fatigue. To measure Pdi and diaphragmatic EMG, three balloon catheter systems have to be swallowed; two of these measure esophageal and gastric pressures and the third one, usually a Swan-Ganz catheter records diaphragmatic EMG. In the present study we describe how a thermodilution Swan-Ganz pacing catheter can be very simply modified to measure both Pdi and diaphragm EMG. Because only one catheter has to be swallowed, subject's acceptability improves, particularly for repeated measurements in the same subject. We have used such a catheter system for more than 18 months to study respiratory muscle fatigue in man. The measurements of Pdi by the modified Swan-Ganz catheter compare well with those recorded simultaneously with conventional balloons, and in vitro frequency response measurements showed that amplitude responses differed by 2% at 2 1/2 Hz. Phase responses of the esophageal and gastric balloons were linear over the range of frequencies tested.

Catheterization↗
PubMed1987

Cell lineages in peripheral nervous system ontogeny: medium-induced modulation of neuronal phenotypic expression in neural crest cell cultures.

Neural crest, taken from cephalic and trunk levels of quail embryos, was grown in vitro in conventional tissue culture medium (Dulbecco's modified Eagle's medium containing 15% fetal calf serum and either 2 or 15% chick embryo extract (CEE] or in a chemically defined serum- and CEE-free medium. Depending on the conditions employed, different types of neuronal or neuronlike cells developed in the cultures. Thus, in medium containing 15% CEE, adrenergic cells (identified by tyrosine hydroxylase immunoreactivity and catecholamine histofluorescence) emerged after 5-6 days. These cells lacked tetanus toxin binding sites and did not react with an antibody directed against 70-kDa neurofilament protein. In the fully defined medium, a neuronal cell type exhibiting neurofilament and substance P (SP) immunoreactivity differentiated from noncycling precursors within 1 or 2 days of culture. If serum was added to the medium, the neurites disintegrated and the neuronal cells ultimately died. By sequentially culturing neural crest, first in the wholly synthetic medium for 1-3 days and then in the conventional medium supplemented with serum and 15% CEE, the disappearance of the SP-positive neurons was followed, several days later, by the emergence of adrenergic cells. The majority of these cells and/or their precursors were found to undergo cell division in culture. We conclude that the cells expressing the adrenergic phenotype (characteristic of the sympathetic nervous system) and those displaying SP immunoreactivity, comparable to a category of neurons in dorsal root and cranial sensory ganglia, derive from distinct sets of precursors. Our results reinforce the contention, deduced from in ovo transplantation experiments (see N. M. Le Douarin, (1984) In Cellular and Molecular Biology of Neuronal Development (I. Black, Ed.), pp. 3-28. Plenum, New York), that at least two lineages, from which sensory and autonomic cell types are derived respectively, are segregated early during neural crest ontogeny and have extremely different survival and trophic requirements.

Acetylcholine↗
PubMed1987

A rat histone H4 gene closely associated with the testis-specific H1t gene.

A rat histone H4 gene closely associated with the testis-specific H1t gene was isolated by screening the Sargent-Bonner rat genomic library using cloned human histone genes as probes. Both the H4 gene and the H1t gene are located on a 7-kb EcoRI genomic DNA fragment. Although the deduced amino acid sequence of the rat H4 histone is identical to that of the sequence of human histone H4, the nucleotide sequence of the coding region differs significantly from the coding region of the human H4 gene. Moreover, the relative spacing between the 5'-consensus sequence elements is unique for an H4 gene. S1-nuclease protection analyses reveal that both the H4 and H1t mRNA species are present in a fraction of rat testis cells highly enriched in pachytene spermatocytes, while only the H4 mRNA species is present in a rat myeloma cell line (Y3-Ag1.2.3). During a 1-h hydroxyurea treatment of the Y3 cells, which produces a 99% inhibition of DNA synthesis, the level of this H4 mRNA drops by only 50%, indicating that the stability of this mRNA is only partially coupled with DNA synthesis.

Amino Acid Sequence↗
PubMed1987

Rapid growth of an intact human liver transplanted into a recipient larger than the donor.

Two individuals undergoing orthotopic hepatic transplantation received livers from donors who were on average 10 kg smaller than themselves based on recipient ideal body weight. As a result, the donor livers in these 2 cases were 29%-59% smaller than would be expected had the donor liver and recipient been matched ideally. The liver grafts in the recipients steadily increased in size, as determined by serial computed tomography scanning, to achieve new volumes consistent with those that would have been expected in a normal individual of the recipient's size, sex, and age. Fasting plasma levels of amino acids, glucagon, insulin, and standard liver injury tests were monitored to determine which measure best reflected the changes observed in the size of the grafts over time. No relationship between the changes observed in any of these parameters and hepatic growth was apparent. In both cases, the liver increased in volume at a rate of approximately 70 ml/day. These data demonstrate that a small-for-size liver transplanted into a larger recipient increases in size at a rate of approximately 70 ml/day until it achieves a liver volume consistent with that expected given the recipient's size, age, and sex.

Adolescent↗
PubMed1987

Left-handedness: its association with allergic disease.

It has been postulated that anomalous cerebral dominance is associated with disorders of the immune system and increased incidence of autoimmune diseases has been reported in left-handed individuals. In this study, 313 patients attending an allergy clinic were assessed for left- and right-handedness, using the Edinburgh Handedness Inventory. The results were compared to those in 350 age- and sex-matched control individuals. It was found that significantly more (P less than 0.02) left-handers than right-handers attended the clinic. Among atopic patients in general, patients with IgE-mediated symptoms, patients with urticaria and patients with eczema, there was a highly significant increase in left-handers (P less than 0.005). The results are discussed in terms of dominance.

Asthma↗
PubMed1987

Developmental capacities of avian embryonic dorsal root ganglion cells: neuropeptides and tyrosine hydroxylase in dissociated cell cultures.

Dorsal root ganglia (DRG) from quail embryos of 10-15 days of incubation (E10-15) contain a subpopulation of cells, distinct from postmitotic neurons, that can, under suitable conditions of culture in vitro, differentiate into neuron-like cells that display a variety of adrenergic properties, including tyrosine hydroxylase (TH) immunoreactivity (Xue et al., Proc. Natl. Acad. Sci. U.S.A., 82 (1985) 8800-8804). The present study was undertaken to determine whether other markers typical of autonomic sympathetic nerve cells are also expressed in the same system. Cells immunoreactive for vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY) were found to differentiate continually from non-dividing precursors in all cultures of dissociated E10 quail DRG grown in the presence of chick embryo extract. Whereas VIP was already present (in a minute number of cells) in DRG in situ, NPY could not be detected before 3 days of culture, when it appeared simultaneously with TH. Double immunostaining experiments showed that most VIP-positive cells and about half the NPY-positive cells also displayed TH-immunoreactivity. On the other hand, there was no overlap between the substance P-containing neuronal population and any of the cells containing TH, NPY or VIP. These observations are pertinent to the problem of the segregation of autonomic and sensory cell lines during peripheral nervous system ontogeny.

Animals↗
PubMed1987

Recruitment in the Cooperative Study of Sickle Cell Disease (CSSCD).

The Cooperative Study of Sickle Cell Disease (CSSCD) is a multiinstitutional investigation of the natural history of clinical course of sickle cell disease from birth through adulthood. The study is not a trial; rather, it involves data collection at 23 institutions in a uniform, standardized fashion on 3800 patients. Recruitment aspects that were addressed include issues related to recruitment of different age groups, ranging from newborns to pregnant women to patients over 50 years of age; the need to include mildly affected patients to ensure that the study would not reflect only a severe hospital-based population; recruitment from rural populations; and the need to screen and enter a newborn population at birth. The recruitment goal of entering 3200 patients, including 2100 patients with SS hemoglobinopathy, over a 24-month period was accomplished after 27 months.

Age Factors↗
PubMed1987

Sex steroid replacement in post-menopausal women: effects on thyroid hormone status.

We have measured serum thyroxine (T4), triidothyronine (T3), thyroid-stimulating hormone (TSH) free thyroxine (FT4) and thyroxine-binding globulin (TBG) levels in a total of 5 post-menopausal women who were receiving oestrogen alone (Premarin, n = 19), progestogen alone (Primolut-N, n = 12), a combination of oestrogen and progestogen (Prempak C, n = 14) or no treatment (control group, n = 12). No differences were observed between the Premarin and Prempak C groups; both exhibited elevated T4 and TBG levels, although free thyroxin (FT4) and T4/TBG concentrations were normal relative to those in the control group. The Primolut-N subjects showed subnormal T3 and FT4 levels relative to the controls. It was concluded that it is not possible to make general statements regarding the effects of sex steroids on FT4 levels.

Estrogens, Conjugated (USP)↗
PubMed1987

Cleavage from the N-terminal region of beta Bp crystallin during aging of the human lens.

Polyclonal antisera have been made to synthetic peptides that correspond to the N-terminal (residues 1-12) and C-terminal (residues 195-204) sequences of bovine beta Bp crystallin. Both anti-beta Bp1-12 and anti-beta Bp195-204 recognize specifically the beta Bp component of bovine lens. In the young human lens, anti-beta Bp195-204 recognizes predominantly the 26,000 MW form of beta Bp, while in older lenses this same antiserum recognizes mainly the 22,000 MW in vivo proteolysis product. In contrast, during aging of the normal human lens anti-beta Bp1-12 recognizes only decreasing amounts of the 26,000 MW form of beta Bp, with no binding to the 22,000 MW form of this polypeptide. These results suggest that during aging of the normal human lens, the N-terminus of beta Bp is the preferred site of in vivo proteolysis.

Adolescent↗
PubMed1987

Stab wounds to the abdomen: failure of blunt probing to predict peritoneal penetration.

A study was conducted to examine the usefulness of blunt probing for evaluation of penetrating abdominal trauma. Ten anesthetized adult beagles weighing 8 to 17 kg were sacrificed by ventricular fibrillation following a standardized resuscitation protocol. Immediately thereafter, the abdomen was shaved and ten stab wounds were placed in the abdomen of each dog with #11 blade. A separate individual probed the wounds sequentially with a cotton swab and predicted on the basis of this examination whether the wound penetrated the parietal peritoneum (deep) or not (superficial). The abdomen then was opened and reflected, by a midline incision, and peritoneal penetration was verified visually by two observers. Statistical analysis of data was performed using the z test for binomial proportions. Fifty-nine of the 100 wounds were found to penetrate the parietal peritoneum. Examiners predicted 35 correctly, but called 24 of 59 superficial. Thirty-eight of 41 superficial wounds were identified correctly; three were incorrectly called deep. Sensitivity was .59 (z = 1.432, P greater than .5); specificity was .93 (z = 5.466, P less than .001). Blunt probing may be a useful technique if peritoneal penetration is determined, but it is inaccurate in predicting peritoneal nonpenetration. If violation of the peritoneum is not determined with this technique, other methods must be used.

Abdominal Injuries↗
PubMed1987

Thyroid dysfunction in institutionalised Down's syndrome adults.

This study of 111 institutionalised Down's syndrome subjects and 74 controls found a relatively low risk of hypothyroidism in both groups compared with certain other studies of Down's subjects, which found very high rates of thyroid hypofunction. However, the Down's syndrome group had a significantly raised risk of hypothyroidism (9%), hyperthyroidism (1.8%) and the presence of thyroid microsomal antibodies (29%) compared with the controls and with laboratory reference data. It is recommended that thyroid function testing should be routine in older Down's syndrome subjects, with special attention being given to the clinical status of those with microsomal antibodies present.

Adult↗
PubMed1987

Using perceived exertion to prescribe and monitor exercise training heart rate.

We examined whether feedback of heart rate (HR) or HR combined with ratings of perceived exertion (RPE and HR) during a graded exercise test (GXT) and during early trials of field training would reduce the errors commonly seen when training heart rate range (THR) is self-monitored by participants. Asymptomatic males (n = 24) were tested on a Balke treadmill protocol in a randomized, between-groups design under control conditions or conditions where feedback about HR or HR combined with RPE were given as age-predicted THR was approximated. This was followed on alternating days by three field trials of an 800-m jog where errors between prescribed and attained THR were fed back to each subject. A priori 95% confidence intervals for the first field trial showed that signed (algebraic) error for the HR combined with RPE condition (+3 bts/min) was less than for controls (+23.5 bts/min). Feedback of HR alone was no different from the control condition. All groups showed increased accuracy (P less than .05) by the third field trial [absolute error: T1 (18 bts/min) to T3 (9.6 bts/min); signed error: T1 (+14 bts/min) to T3 (+4 bts/min)]. Our results suggest feedback of HR combined with RPE during a GXT may reduce an overshoot in THR during the first of subsequent exercise sessions. Feedback of HR alone appeared sufficient to further reduce THR errors after a third exercise session in the field. The procedures used may have practical importance for sedentary, unfit, or diseased individuals where conservative HR prescriptions are desirable but electronic monitoring is not feasible or cost effective.

Adult↗
PubMed1987

Direct measurement of hydration-related dynamic changes in lysozyme using inelastic neutron scattering spectroscopy.

Inelastic neutron scattering spectroscopy is used to investigate dynamic changes in lysozyme powder at two different low D2O hydrations (0.07g D2O/g protein and 0.20 g D2O/g protein). In the higher hydration sample, the inelastic scattering between 0.8 and 4.0 cm-1 energy transfer is increased and the elastic scattering is decreased. The decreased elastic scattering suggests increased atomic amplitudes of motion and the increased 0.8 to 4.0 cm-1 scattering suggests increased motions in this frequency range. Comparison with normal mode models of lysozyme dynamics shows that the inelastic difference occurs in the frequency region predicted for the lowest frequency, largest amplitude, global modes of the molecular [M. Levitt, C. Sander and P.S. Stern, J. Mol. Biol. 181, 423 (1985). B. Brooks and M. Karplus, Proc. Natl. Acad. Sci (U.S.A) 82, 4995 (1985), R.E. Bruccoleri, M. Karplus and J.A. McCammon, Biopolymers 25 1767 (1986)]. Our results are consistent with a model in which an increased number of low frequency global modes are present in the higher hydrated sample.

Energy Transfer↗