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Biomedical subjects

S B Freeman

Publications and source records attributed to S B Freeman.

34 records · Page 2Linked to original sources
PubMed1991

Molecular studies of non-disjunction in trisomy 16.

The origin of the additional chromosome in 26 trisomy 16 spontaneous abortions was studied using DNA probes for chromosome 16, including a probe for centromeric alpha sequences. We were able to determine the parent and meiotic stage of origin of trisomy in 22 cases, with all being attributable to maternal meiosis I non-disjunction. Furthermore, in each of the remaining four cases the results were compatible with this origin. Thus, it is likely that the high incidence of trisomy 16 results from an abnormal process acting at maternal meiosis I which more frequently involves chromosome 16 than other similar sized chromosomes. In studies of recombination, we found little evidence for an association between reduced or absent recombination and chromosome 16 non-disjunction; however, we were unable to rule out an effect of hyperrecombination.

Cells, Cultured↗
PubMed1991

Intraoperative radiotherapy of skull base cancer.

As the head and neck surgeon expands the boundaries of resectability into the skull base, the margin of tumor clearance diminishes. Intraoperative radiotherapy (IORT) can be used as an adjunct to skull base surgery and external beam radiation to enhance local control in areas with close margins or remaining microscopic disease. During the period from May 1982 to May 1988, 25 patients underwent IORT of the skull base following resection and prior to closure to treat microscopic disease in 9 patients, sterilize close margins in 14 patients, and attempt to eliminate remaining gross disease in 2 patients. The types of tumors treated were 13 squamous cell carcinomas, 4 adenoid cystic carcinomas, 3 high-grade mucoepidermoid carcinomas, 3 sarcomas, 1 malignant mixed tumor, and an oncocytic adenocarcinoma. The majority of the tumors either originated in the sinuses or were skull base extensions of oral cavity or oropharyngeal cancers. In 22 patients with 1-year follow-up, IORT prevented local recurrence in 14 (64%) patients. This may represent improved control of local disease in patients who historically have a very dismal prognosis. The indications, techniques, and complications of this exciting therapeutic modality are also reviewed.

Adolescent↗
PubMed1991

Management of perimenopausal symptoms.

The perimenopausal period brings about many changes. The significance of many of the signs and symptoms associated with menses also may change. Premenstrual syndrome (PMS) and uterine bleeding need close follow-up during the perimenopausal period. Urinary incontinence appears to worsen because of hormonal changes occurring during the climacteric. All three of these conditions present a special challenge to the health care practitioner.

Female↗
PubMed1991

Trisomy 21: association between reduced recombination and nondisjunction.

To assess the association between recombination and nondisjunction of chromosome 21, we analyzed cytogenetic and DNA markers in 104 trisomy 21 individuals and their parents. Our DNA marker studies of parental origin were informative in 100 cases, with the overwhelming majority (94) being maternal in origin. This value is significantly higher than the 75%-80% maternal nondisjunction rate typically observed in cytogenetic studies of trisomy 21 and illustrates the increased accuracy of the molecular approach. Using the maternally derived cases and probing at 19 polymorphic sites on chromosome 21, we created a genetic map that spans most of the long arm of chromosome 21. The map was significantly shorter than the normal female linkage map, indicating that absence of pairing and/or recombination contributes to nondisjunction in a substantial proportion of cases of trisomy 21.

Adult↗
PubMed1991

Management of anterior and posterior epistaxis.

Management of epistaxis is directly related to the site of the bleeding. Anterior nosebleeds are the least dangerous and the most common, especially among children. Sinus disease, colds, allergies, abrupt temperature changes and dry heat produce fragile and hyperemic nasal mucosa that bleeds easily with nose blowing or mild abrasion. Anterior epistaxis can be reached easily and stopped by pinching the nostrils, applying silver nitrate cautery or lightly packing the anterior nose. Posterior epistaxis may be severe and may be more difficult to locate and control. Occurring more often in the elderly, posterior nosebleeds are frequently associated with hypertension, atherosclerosis and conditions that decrease platelets and clotting function. Visualization of the bleeding site is enhanced by proper positioning of the patient, use of topical vasoconstricting anesthesia and suctioning. Anterior and posterior nasal packing, hospitalization, antibiotics and close follow-up may be required to control posterior nosebleeds.

Aged↗
PubMed1990

Intraoperative radiotherapy of head and neck cancer.

Intraoperative radiotherapy (IORT) was developed as an adjuvant to surgery and external beam radiation for aggressive, extensive, or recurrent cancers of the head and neck. This report reviews the indications, technique, response, and complications of IORT. From May 1982 to May 1988, 104 patients received 15 to 20 Gy of radiation delivered through a Lucite cone to areas of high risk of recurrence following resection and prior to closure. The indications for treatment were (1) aggressive primary or recurrent cancer; (2) disease fixed to deep muscle, carotid, or bone; or (3) close margins in an effort to preserve vital structures or function. The IORT was effective in preventing local recurrence in 14 (40%) of 35 patients with 2-year follow-up of squamous cell carcinoma. The complication rate was acceptable. Intraoperative radiotherapy appears to be a safe and beneficial adjunctive therapy for cancers that historically have extremely dismal prognoses.

Adolescent↗
PubMed1990

Metastasizing pleomorphic adenoma of the nasal septum.

Pleomorphic adenoma is the most common benign tumor of glandular tissue occurring in the head and neck region. There have been several reports of metastasis of this benign-appearing tumor from the salivary glands to distant sites, suggesting hematogenous spread and implantation. Although occurrence of pleomorphic adenoma on the nasal septum has been described, to our knowledge this is the first reported case of recurrent septal pleomorphic adenoma with histologically benign tissue in an enlarged metastatic ipsilateral submandibular lymph node, suggesting lymphatic spread. The literature concerning the subject is reviewed. Wide septal excision and modified neck dissection is the recommended treatment.

Adenoma, Pleomorphic↗
PubMed1990

Assignment of X-linked hydrocephalus to Xq28 by linkage analysis.

X-linked recessive hydrocephalus (HSAS) occurs at a frequency of approximately 1 per 30,000 male births and consists of hydrocephalus, stenosis of the aqueduct of Sylvius, mental retardation, spastic paraparesis, and clasped thumbs. Prenatal diagnosis of affected males by ultrasonographic detection of hydrocephalus is unreliable because hydrocephalus may be absent antenatally. Furthermore, carrier detection in females is not possible because they are asymptomatic. Using four families segregating HSAS, we performed linkage analysis with a panel of X-linked probes that detect restriction fragment length polymorphisms. We report here that HSAS, in all tested families, is closely linked to marker loci mapping in Xq28 (DXS52, lod = 6.52 at theta of 0.03; F8, lod = 4.32 at theta of 0.00; DXS15, lod = 3.40 at theta of 0.00). These data assign HSAS to the gene-dense chromosomal band Xq28 and allow for both prenatal diagnosis and carrier detection by linkage analysis.

Blotting, Southern↗
PubMed1989

Prenatal ascertainment of triploidy by maternal serum alpha-fetoprotein screening.

We report our experience in ascertaining fetal triploidy during routine maternal serum alpha-fetoprotein (MSAFP) screening. Three cases were identified after elevated MSAFP tests. Two of the three had normal amniotic fluid alpha-fetoprotein (AFAFP). The third had amniocentesis too late for AFAFP interpretation. Three additional cases were detected by amniocentesis without prior MSAFP screening and none had an elevated AFAFP. A literature review revealed eight triploid fetuses detected as a result of an elevated MSAFP. Of the five with AFAFP quantitation, only one had an abnormal value and the elevation was minimal. In these 14 cases from our own and other reports, ultrasound findings of placental and fetal abnormalities were often noted, but a pattern diagnostic of triploidy was not present. We conclude that, for optimal prenatal detection of triploidy, fetal karyotyping should be included when an amniocentesis is performed for elevated MSAFP.

Adult↗
PubMed1985

Dose-related response of centrally administered epinephrine on the change in aortic diastolic pressure during closed-chest massage in dogs.

The current recommendation of the American Heart Association is to give 0.5 to 1.0 mg (7.5 to 15 micrograms/kg in a 70-kg man) of epinephrine intravenously every five minutes during cardiac arrest. The optimal dose of epinephrine to augment the aortic diastolic pressure (ADP) is not known. The effect of various doses of central bolus epinephrine on the ADP during closed-chest massage was studied. A group of 25 large dogs was divided equally into five groups: control and 15, 45, 75, and 150 micrograms/kg. After three minutes of cardiac arrest, closed-chest massage was initiated, and the study drug was given two minutes later. The ADP and right atrial pressures were monitored for 15 minutes. Changes in ADP peaked at two minutes after injection in all groups receiving epinephrine, and the drop in ADP over time noted in the control group was prevented by increasing doses of epinephrine. Among the groups receiving epinephrine, however, there was no difference in the absolute ADP and diastolic coronary perfusion pressure.

Animals↗
PubMed1983

Hemodynamics of cardiac massage.

The introduction of closed chest massage in 1960 initiated a widespread interest in cardiopulmonary resuscitation. Until that time, open chest cardiac massage was the standard for CPR. Initial explanations for blood flow during closed chest CPR were based upon direct compression of the heart. This explanation has given way to demonstrations that blood flows during CPR because of changes in intrathoracic pressure. Changes in intrathoracic pressure that create blood flow have been created by simple maneuvers such as coughing. More involved methods of affecting intrathoracic pressure, in an attempt to improve upon standard closed chest massage, have included applying positive pressure to the airway, binding of the abdomen, and the use of MAST. Cardiac output with closed chest massage is approximately one fourth of normal, and cerebral perfusion is approximately one tenth of normal. Cardiac output with open chest massage is approximately double that obtained by closed chest massage. Cerebral blood flow during open chest massage approaches physiologic values. The use of drugs possessing alpha adrenergic activity and maneuvers that augment intrathoracic pressure improve vital organ perfusion.

Animals↗
PubMedDate not supplied

Risk factors for trisomy 21: maternal cigarette smoking and oral contraceptive use in a population-based case-control study.

PURPOSE: We examined maternal smoking and oral contraceptive use as possible risk factors in the genesis of cases of trisomy 21 of maternal origin. This is the first epidemiological study to categorize cases of trisomy 21 by parent of origin and timing of the meiotic error before assessing possible risk factors. METHODS: We used chromosome 21-specific DNA markers to assign origin to each case. Structured interviews were employed to determine maternal smoking and oral contraceptive use around conception. RESULTS: The odds ratio (OR) for maternal smoking was significantly increased among younger mothers (OR = 2.98; 95% CI = 1.01-8.87), but only in a particular subset of meiotically-derived cases. The combined use of cigarettes and oral contraceptives increased the risk further (OR = 7.62; 95% CI = 1.63-35.6); however, oral contraceptive use alone was not a significant risk factor. CONCLUSION: Our results indicate that categorizing cases of trisomy 21 by parent and timing of the meiotic error allows more precision in identifying risk factors and may shed light on mechanisms of meiotic nondisjunction.

Adult↗
PubMedDate not supplied

Communication patterns and decision making among parents and health care providers in the neonatal intensive care unit: a case study.

This case study illustrates salient issues in the communication and decision making of parents in a neonatal intensive care unit. The case provides descriptions that may be typical features of interaction between parents and professionals in a neonatal intensive care unit. Conclusions are drawn from this case with recommendations for practice.

Communication↗