Should results of ultrasound Doppler studies be reported in units of frequency or velocity?

There is a current tendency to report the results of ultrasound Doppler studies in units of velocity instead of Doppler frequency. This is probably motivated by the intuitive feeling that blood flow studies should naturally be reported in cm/s and the notion that "velocity" is a normalizing factor for Doppler ultrasound studies. In order to determine velocity, the Doppler angle theta or angle formed by the ultrasound beam and flow velocity vector, must be known. It is not possible, using currently available systems, to obtain an accurate estimate of this angle. The physics related to the Doppler equation are reviewed in this paper along with examples to illustrate the origin and magnitude of errors that could arise when reporting in units of velocity. Guidelines are provided for thinking about and reporting results of Doppler studies in units of velocity. An understanding of the Doppler equation and its use in clinical studies are promoted in this paper to enhance the diagnostic usefulness of Doppler ultrasound studies and to reduce serious errors which could lead to faulty information dictating patient management.     

Development of attraction to estrous females in male dogs

In simultaneous choice tests male beagles were allowed to visit a caged female in estrus, or caged, spayed female not in estrus. Males were tested periodically from 1-3 to 22-24 months of age. The 3 subject groups were normal males (Group N), males castrated 4-7 days postpartum and injected with testosterone propionate (TP) until they were 3 months old (Group TPTC), and males castrated 4-7 days but given no hormone treatment, i.e., untreated castrates (Group UC). A statistically reliable preference for visiting the estrous rather than the nonestrous female first appeared in N males at 4-6 months, in TPTC males at 1-3 months, and in UC males at 10-12 months. In N males attraction to the estrous female (measured by time spent visiting her) increased progressively from 4-6 to 16-18 months. In the same period concentration of plasma testosterone rapidly increased, reached a peak at 10-12 months, and then declined. UC males exhibited no significant increase in attraction to the estrous female from 10-12 months (when a preference first appeared) to 22-24 months. They then received 10 injections of TP after which their visiting time to the estrous female was equal to that of N males. TPTC males exhibited a precocious preference for the estrous female at 1-3 months, while they were receiving TP, and there was no decrease in strength of attraction in the following 9 months during which time no hormone was administered. Between 10-12 and 13-15 months, still without exogenous androgen, visiting to the estrous female began to increase and continued to do so until 19-21 months.     

Isolation of a new clathrin heavy chain gene with muscle-specific expression from the region commonly deleted in velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) and DiGeorge syndrome (DGS) are developmental disorders characterized by a spectrum of phenotypes including velopharyngeal insufficiency, conotruncal heart defects and facial dysmorphology among others. Eighty to eighty-five percent of VCFS/DGS patients are hemizygous for a portion of chromosome 22. It is likely that the genes encoded by this region play a role in the etiology of the phenotypes associated with the disorders. Using a cDNA selection protocol, we isolated a novel clathrin heavy chain cDNA (CLTD) from the VCFS/DGS minimally deleted interval. The cDNA encodes a protein of 1638 amino acids. CLTD shares significant homology, but is not identical to the ubiquitously expressed clathrin heavy chain gene. The CLTD gene also shows a unique pattern of expression, having its maximal level of expression in skeletal muscle. Velopharyngeal insufficiency and muscle weakness are common features of VCFS patients. Based on the location and expression pattern of CLTD, we suggest hemizygosity at this locus may play a role in the etiology of one of the VCFS-associated phenotypes.      

Rapid intraoperative immunohistochemical evaluation of sentinel lymph nodes for metastatic breast carcinoma.

OBJECTIVE: Sentinel lymph node (SLN) biopsy is an integral part of the surgical management of patients with breast cancer. Rapid immunohistochemistry (RIHC) has the potential to increase detection of metastatic carcinoma at the time of frozen section consultation. The authors assessed the accuracy and turnaround time of a newly developed RIHC method for pancytokeratin (RIHC-CK). METHODS: Sixty-six SLNs from 32 patients with breast carcinoma were examined for metastasis using the Zymed Sentinel Lymph Node Rapid IHC Kit. Intraoperative frozen sections (6 mum) of the SLNs were incubated with Zymed anti-pan-cytokeratin/HRP conjugate, diaminobenzidine (DAB), and stained with hematoxylin. Slides were ready within 8 minutes and were interpreted as positive or negative for metastatic carcinoma. Results were compared with previous intraoperative touch preparations, frozen sections, hematoxylin and eosin (Perm H&E), and AEl/3-immunostained permanent sections (Perm CK). RESULTS: Fourteen lymph nodes (19%) in 13 patients tested positive for metastatic carcinoma in Perm H&E, the gold standard. RIHC-CK had the highest sensitivity (92%) of the intraoperative tests, compared with touch preparations (64%) and frozen sections (80%). RIHC-CK showed 94% accuracy, compared with 96% (frozen section) and 93% (touch preparation). The RIHC technique took 8 minutes and was easy to perform and interpret. CONCLUSIONS: Zymed RIHC is a sensitive method for detecting breast cancer metastases in SLNs. The speed, accuracy, and ease of interpretation of the test allow for recognition of micrometastases (<2 mm) that might otherwise be undetectable by current methods of intraoperative evaluation. The prognostic significance and effect on surgical management of micrometastases in SLNs have yet to be determined.     

Effects of gonadal hormones on urinary behavior in dogs

The effects of testicular and ovarian hormones on urinary frequency and posture were studied in 8 groups of dogs. Three of the 4 female groups had been exposed to androgenic stimulation in utero, neonatally, or both in utero and in infancy. The fourth group of females consisted of ovariectomized controls. Males were intact or castrated as adults, as juveniles, or as neonates. Frequency of urination was increased in all groups by estrogen and by testosterone. Urinary posture was unaffected in males by castration in the adult or juvenile stages. Neonatal castration of males resulted in periodic regression from the adult male posture to the immature male posture. Control and prenatally androgenized females urinated in the feminine position. Females treated with large amounts of testosterone in infancy showed a limited degree of masculinization of urinary posture. Females exposed to testosterone before and immediately after birth urinated as females about 50% of the time and as adult males for approximately half of their urinations. Exogenous estrogen or androgen administered in adulthood had no effect on posture assumed for urination.     

The importance of the pharmacist's expanding role on the diabetes team: reinforcing nutritional guidelines for improved glycemic control

The role of the pharmacist on the diabetes care team is expanding due to the increasing number of patients diagnosed with diabetes, limited health care dollars, and the education related to and required for patients by managed care organizations and insurance companies. In the past, training of patients in diabetes self-management skills has been inadequate, and this continues to be the case. Clinical pharmacists, in cooperation with physicians, have increased opportunities to provide education about medications and may include instructions for patients regarding the interaction of food consumed with changes in blood glucose levels. Because of monthly refills on prescribed medications, a patient's interaction with the pharmacist in the setting of a commercial pharmacy is more frequent than with any other member of the diabetes team. This contact offers an ideal educational opportunity. The action and efficacy of medications that affect the pancreas, hepatic glucose production, the utilization of glucose by muscle cells, and the absorption of glucose from the intestines are influenced directly by the meal plan. Nutritional guidelines, meal planning for the Type I and Type II patient, use of the exchange system, carbohydrate counting, artificial sweeteners, alcoholic beverages, and suggestions for guiding patients to establish eating habits that lead to improved diabetes control are important issues for every member of the diabetes team to address. The reinforcement of dietary principles may occur in the educational setting of the hospital or the clinic or within the commercial pharmacy setting. When the team presents accurate and current information, continuity of care and improved patient understanding are achieved.     

Effect of dietary sodium on airways responsiveness and its importance in the epidemiology of asthma: an evaluation in three areas of northern England.

BACKGROUND--Although several investigations have shown a relationship between asthma (or its surrogate, airways responsiveness) and dietary or urinary sodium, others have not, and the matter remains controversial. This "salt effect" has been investigated during two recent epidemiological surveys of men in northern England. The first assessed the possible effect on airways responsiveness of occupational exposure to welding fumes, and the second characterised airways responsiveness in two geographically distinct residential areas. Thus, three separate study areas/populations were involved. METHODS--Investigation 1 involved 1059 shipyard workers aged 16-27 years who were exposed variously to welding fumes, and Investigation 2 involved 587 men aged 20-44 years who lived in rural West Cumbria or in urban Newcastle upon Tyne. In Investigation 1, a 24 hour urine specimen was requested from each subject with quantifiable airways responsiveness (PD20 < or = 6400 micrograms methacholine) and from an equal number of subjects without measurable airways responsiveness from the same occupational subgroup. In Investigation 2, every subject was asked to provide a 24 hour urine specimen. RESULTS--Of the men undergoing methacholine tests, satisfactory 24 hour urine specimens were obtained from 234 (22.1%) in Investigation 1 and 232 (39.5%) in Investigation 2. Analysis using multiple linear regression, multiple linear logistic regression, and multiple regression for censored data produced consistent results within each study population but conflicting results between them, such that there was no hint of a relationship between airways responsiveness and 24 hour urinary sodium excretion in the shipyard workers of Investigation 1 nor in the rural West Cumbrian population of Investigation 2, but an association was found in the urban Newcastle population of Investigation 2. All study populations were sufficiently large to demonstrate anticipated relationships between airways responsiveness and atopy, baseline FEV1, and (Newcastle only) age. CONCLUSIONS--If airways responsiveness is related to dietary sodium the relationship is not likely to be strong.     

Contrast agent neurotoxicity presenting as subarachnoid hemorrhage

A patient developed signs, symptoms, and radiologic findings compatible with acute subarachnoid hemorrhage after receiving a large dose of heparin and intravascular contrast medium for coronary angiography and stent placement. Subsequent CT indicated the subarachnoid enhancement was due to contrast. Neurotoxicity from contrast agents is well-known, however this is an unusual report of toxicity mimicking subarachnoid hemorrhage clinically and radiologically.