Racial/Ethnic Trends in Virtual Mental Health Care Utilization Among Undergraduate Students: A Descriptive Study

BACKGROUND

Undergraduate students are particularly in need of mental health support, but demand has far surpassed resources. This gap between mental health diagnoses and support is particularly large among Asian, Hispanic/Latinx, and Black students. Supplementing on-campus care with a virtual-only behavioral health partner may shift these trends.

OBJECTIVE

This study is aimed at comparing the number of undergraduate students from different racial/ethnic groups (White, Asian, Islander, Hispanic/Latinx, Black, Native, and Multiracial) engaging in virtual mental health visits as part of a partnership with a company providing virtual-only care, with the total enrolled undergraduate students at the same 113 institutions.

METHODS

We used de-identified visit data and self-reported race/ethnicity to define the "patient" population of undergraduates accessing care. We compared that to the full "student" population of undergraduates among the same schools, available as part of the Integrated Postsecondary Education Data System (IPEDS).

RESULTS

Patient population race/ethnicity (N = 14,870) differed significantly from student population race/ethnicity (N = 619,459). A significant effect ( χ 26 = 2258, P < .001) indicated that patient demographics differed from student demographics. We found proportionally more Asian, Black, and Multiracial patients than students. At the same time, we found proportionally fewer White and Hispanic/Latinx patients than students.

CONCLUSIONS

We conclude that, in contrast to prior literature in traditional mental health care, some racial/ethnic minority undergraduates (Asian, Black, and Multiracial) may actually access care at a higher rate under a fully virtual model. On the other hand, White and Hispanic/Latinx students may access care less frequently.

[Update on collaborative autopsy-based research in German pathology, neuropathology, and forensic medicine]

BACKGROUND

Autopsies are a valuable tool for understanding disease, including COVID-19.

MATERIALS AND METHODS

The German Registry of COVID-19 Autopsies (DeRegCOVID), established in April 2020, serves as the electronic backbone of the National Autopsy Network (NATON), launched in early 2022 following DEFEAT PANDEMIcs.

RESULTS

The NATON consortium's interconnected, collaborative autopsy research is enabled by an unprecedented collaboration of 138 individuals at more than 35 German university and non-university autopsy centers through which pathology, neuropathology, and forensic medicine autopsy data including data on biomaterials are collected in DeRegCOVID and tissue-based research and methods development are conducted. More than 145 publications have now emerged from participating autopsy centers, highlighting various basic science and clinical aspects of COVID-19, such as thromboembolic events, organ tropism, SARS-CoV‑2 detection methods, and infectivity of SARS-CoV-2 at autopsy.

CONCLUSIONS

Participating centers have demonstrated the high value of autopsy and autopsy-derived data and biomaterials to modern medicine. The planned long-term continuation and further development of the registry and network, as well as the open and participatory design, will allow the involvement of all interested partners.

Limitations of Immunomagnetic Separation for Detection of the Top Seven Serogroups of Shiga Toxin-Producing Escherichia coli

Shiga toxin-producing Escherichia coli (STEC) strains are foodborne pathogens that negatively impact human health and compromise food safety. Serogroup O157 is the most frequently isolated and studied STEC serogroup, but six others (O26, O45, O103, O111, O121, and O145) have also been identified as significant sources of human disease and collectively have been referred to as the "top six" pathogenic serogroups. Because detection methods for non-O157 serogroups are not yet refined, the objective of this study was to compare the effectiveness of immunomagnetic separation (IMS) for recovery of serogroup O157 isolates with that for each of the top six E. coli serogroups in pure and mixed cultures of STEC at 10³ to 10⁷ CFU/mL. After serogroup-specific IMS, DNA was extracted from cultured isolates to analyze the specificity of each IMS assay using conventional and quantitative PCR. In pure cultures, DNA copy number obtained after IMS was lower for O111 and O157 (P < 0.01) than for other serogroups. Based on quantitative PCR (qPCR) analyses, specificity was reduced for all IMS assays when STEC isolates were mixed at 7 log CFU/mL, although the O157 IMS assays recovered only O157 over a wider range of concentrations than did assays for non-O157 serogroups. At the lowest dilution tested, conventional PCR was specific for all serogroups except O121 and O145. For these two serogroups, no dilution tested recovered only O121 or O145 when evaluated with conventional PCR. Refinements to IMS assays, development of selective media, and determination of optimal enrichment times to reduce background microflora or competition among serogroups would be especially beneficial for recovery of O111, O121, and O145 serogroups to improve STEC detection and isolation.

Heat and desiccation are the predominant factors affecting inactivation of Bacillus licheniformis and Bacillus thuringiensis spores during simulated composting

AIMS

The suitability of composting for disposal of livestock mortalities due to Bacillus anthracis was assessed by measuring viability of surrogate spores from two strains each of Bacillus licheniformis and Bacillus thuringiensis after a heating cycle modelled on a cattle composting study.

METHODS AND RESULTS

Sporulation was attempted from 10 to 37°C, but poor yields at lower temperatures resulted in 25, 30 and 37°C being selected to generate sufficient spores (8 log10  CFU ml(-1) ) for experiments. Spores were inoculated into 3 g autoclaved dried-ground compost rehydrated with 6 ml water or silica beads in a factorial design for each strain, sporulation temperature, matrix and sampling day (0, 25, 50, 100, 150). Maximum incubation temperature was 62°C, but spores were maintained at ≥55°C for 78 of 150 days. Although significant differences existed among Bacillus strains and sporulation temperatures, numbers of viable spores after 150 days averaged 1·3 log10  CFU g(-1) , a 5·2 log10 reduction from day 0.

CONCLUSIONS

Spore inactivation was likely due to heat and desiccation as matrices were autoclaved prior to incubation, negating impacts of microflora.

SIGNIFICANCE AND IMPACT OF STUDY

Results support composting for disposal of anthrax mortalities, provided long-term thermophillic heating is achieved. Due to limited sporulation at 10°C, livestock mortalities from anthrax at this or lower ambient temperatures would likely be of lower risk for disease transmission.

Biomechanical parameter determination of scaffold-free cartilage constructs (SFCCs) with the hyperelastic material models Yeoh, Ogden and Demiray

The biomechanical properties are crucial indicators for the functional characterization of cartilaginous tissue. In this contribution native articular cartilage and three-dimensional scaffold-free cartilage constructs (SFCCs) are characterized by hyperelastic material models (Yeoh, Ogden and Demiray). SFCCs were developed for the therapy of damaged articular cartilage. The normalized error (NE) of fit and experiment is in the range of 0.04 and 0.13. The material model Yeoh with two parameters yields the best fit. The stress-like parameterc 20 is 0.489 MPa for native cartilage, 0.120 MPa and 0.041 MPa for SFCCs produced from mesenchymal stem cells and chondrocytes, respectively. The significance of the fits and the derived parameters are presented and evaluated.

Energy harvesting for active implants: powering a ruminal pH-monitoring system

Energy harvesting is a feasible method to prolong service life of implanted devices. We present a thermal energy harvesting approach for a ruminal pH-monitoring probe in cattle. Thermoelectric generators utilize the temperature gradient between the probe and the ruminal fluid during water intake. The in vivo experiment yielded a maximum electric power of 32 μW.

Clinical and histological features of leprosy and human immunodeficiency virus co-infection in Brazil

BACKGROUND

Both leprosy and human immunodeficiency virus (HIV) are infectious diseases, and are an important global health problem. Patients with leprosy who are co-infected with HIV seem to be at higher risk of developing leprosy reactions.

AIM

To examine the histological features of leprosy in patients with HIV and leprosy co-infection, particularly to determine whether the typical leprosy histopathology is present in skin biopsies, and to assess the histological features of leprosy reactions in co-infected patients.

METHODS

This was a matched cohort study with 11 co-infected patients and 31 HIV-negative patients with leprosy. A structured protocol for skin-biopsy evaluation was followed, focusing on inflammation of the skin and dermal nerves.

RESULTS

Of the 11 HIV-positive patients, 7 (63%) had borderline tuberculoid (BT) leprosy and 5 (70%) of these 7 patients had developed a type 1 reaction. The lesions in these patients were immunologically active, with 100% of biopsies having evidence of compact granulomas, 90% evidence of oedema and 30% evidence of necrosis.

CONCLUSIONS

In this study, patients co-infected with HIV and M. leprae had the typical histological lesions of leprosy. There was evidence of immune activation in patients who received combination antiretroviral therapy, and these patients had BT leprosy and leprosy-upgrading reactions.

High-dose remifentanil prevents development of thermal hyperalgesia in a neuropathic pain model

BACKGROUND

Intraoperative nerve lesions can lead to chronic postoperative pain. There are conflicting data as to whether or not anaesthetics administered intraoperatively are beneficial. We investigated if remifentanil administered at the time of nerve injury was able to attenuate neuropathic hypersensitivity.

METHODS

Rats were anaesthetized with isoflurane, endotracheally intubated, and a tail vein catheter was inserted. Rats received an i.v. infusion of either saline or low- or high-dose remifentanil (2 or 20 μg kg(-1) min(-1), respectively) for 20 min. During this time, rats received a spinal nerve L5 transection to induce neuropathic pain or a sham procedure. Behavioural tests to assess mechanical and cold allodynia and heat hyperalgesia were performed on postoperative days 1, 3, 7, 14, 21, and 28.

RESULTS

Sham-operated animals exhibited no hypersensitivity regardless of the intraoperative remifentanil dose. In rats which received spinal nerve L5 transection, mechanical and cold allodynia developed with no significant differences between treatment groups. However, thermal hyperalgesia was reduced in rats given high-dose remifentanil: mean (standard deviation) area under the curve 426 (53) compared with 363 (34) and 342 (24) in saline or low-dose remifentanil treated rats, respectively (P<0.05).

CONCLUSIONS

High-dose remifentanil administered at the time of transection of the spinal nerve at L5 prevents subsequent thermal hyperalgesia.

Problems of diabetes management in the immigrant population in Germany

AIM

To compare prospectively the effect of diabetes management in the immigrant and the native population in Berlin, Germany.

METHODS

Diabetes patients attending a metabolic outpatient clinic in an area with a high immigrant population were studied at the start of the training program and after 12 months of participation.

RESULTS

1607 of 2099 patients with at least one post-training visit (76.6%) provided analysable data. Of these 362 (22.5%) were immigrants. Initial hemoglobin A1c (HbA1c) was higher in the immigrants. Immigrants were 5 years younger and had a more recent diagnosis of diabetes. HbA1c fell by 1.4 and 1.5 percentage points in the immigrants and natives, leaving a greater proportion of the immigrants above the target value of 6.5%. Analysis of patients matched according to baseline HbA1c, sex and age showed a smaller decrease in mean HbA(1c) for the immigrants. The percent of patients with hypertension, obesity, dyslipidaemia or diabetic complications was comparable in both groups initially and after 12 months.

CONCLUSION

Immigrants had a higher HbA1c concentration at baseline and after 12 months compared to natives, despite a similar decline in HbA1c percentage points. More investigations are warranted to identify the causes, such as dietary habits, language difficulties, education and others.

Pegvisomant increases intra-abdominal fat in patients with acromegaly: a pilot study

OBJECTIVE

Acromegalic patients have increased lipolysis and decreased fat mass as well as reduced insulin sensitivity and glucose intolerance. During somatostatin analog therapy, these changes persist despite GH suppression, but they are now due to drug-induced suppression of insulin secretion. By contrast, during pegvisomant (PEG) therapy, GH no longer stimulates lipolysis due to the blockade of its receptor, while insulin action is unabated. Hence, both insulin sensitivity and fat mass, including intra-abdominal fat, should increase. We therefore studied intra-abdominal fat and insulin resistance in acromegalic patients after a 3-month octreotide-washout period, i.e., during untreated acromegaly, and during PEG treatment.

METHODS

Five acromegalic patients, not controlled on octreotide (OCT) therapy, were studied after 3-month OCT washout and 6-month PEG therapy. Insulin sensitivity was determined by homeostatic model assessment value and hyperinsulinemic, normoglycemic clamp. Subcutaneous and intra-abdominal fat were measured by electron beam computed tomography.

RESULTS

During PEG therapy, all the patients had normal, age-adjusted IGF-I concentrations. Compared with washout, insulin sensitivity (HOMA and M value) was not significantly different. However, intra-abdominal fat mass increased significantly during therapy (median (range) cm(2): 112 (84-480) and 172 (112-524) respectively, P<0.05), while subcutaneous fat was not significantly different. Low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides remained unchanged.

CONCLUSIONS

During PEG therapy of acromegalic patients, intra-abdominal fat increases. Visceral obesity is a risk factor for cardiovascular disease. Hence, confirmation and further studies in a larger cohort of acromegalic patients on PEG treatment are warranted.

[Congenital intestinal lymphangiectasia: a rare differential diagnosis in hypoproteinemia in infants]

BACKGROUND

Congenital intestinal lymphangiectasia is a rare disease in childhood, which may already cause protein-losing enteropathy in newborns.

PATIENT, METHODS AND RESULTS

This is a case report of an infant with generalized edema and protein-losing enteropathy, in whom intestinal lymphangiectasia was diagnosed at the age of two months. Following repetitive intravenous albumin und gamma globulin infusions, the elimination of long-chain fats from the diet and the substitution with medium-chain triglycerides (MCT) led to an improvement of the protein-losing enteropathy.

CONCLUSION

In newborns with low level of serum protein and edema protein-losing enteropathy caused by congenital lymphangiectasia might be considered as a differential diagnosis.

Detection of feed-ingested plant DNA fragments in a raw meat product for human consumption

To investigate the potential for foreign DNA in swine tissue to persist in foods for human consumption, a raw meat product (gammon) was prepared from gluteus maximus samples in which plant DNA was present. Degradation of DNA during salt-curing was evident, but a 140-bp fragment of maize chloroplast DNA remained detectable in 6 of 12 samples analyzed. Key words: Food, gammon, genetically modified organism, maize, PCR, pig

Prevalence of aspirin resistance in patients with type 2 diabetes

Aspirin resistance has been recognised to occur in patients with cardiovascular disease and is associated with poor clinical prognosis. The purpose of the present study was to evaluate the prevalence of aspirin resistance in 172 patients with diabetes mellitus type 2 (DM-2). Platelet function of 172 consecutive patients with type 2 diabetes on chronic aspirin therapy was evaluated. The effect of aspirin was assessed using the platelet function analyser (PFA-100) system, reporting platelet-dependent thrombus formation as the time required to close a small aperture in a biologically active membrane. Resistance to aspirin was defined as a normal collagen/epinephrine-induced closure time (82-165 s). Aspirin responders were defined when closure time was > or =300 s. Thirty-seven (21.5%) of the type 2 diabetic patients were found to be resistant to chronic aspirin therapy, 29 (16.9%) were semi-responders and 106 (61.6%) were responders. Univariate analysis revealed that aspirin non-responders were significantly younger (p<0.05) compared to aspirin responders. A significant number of type 2 diabetic patients are resistant to aspirin therapy. Aspirin resistance can be evaluated by point-of-care testing and should be recognised in diabetic patients that are treated for primary or secondary prevention.

Investigations on genetically modified maize (Bt-maize) in pig nutrition: fattening performance and slaughtering results

A grower finisher performance trial with forty-eight pigs was designed to compare the growth performance of pigs fed diets containing either genetically modified (GM) Bt-maize (NX6262) or its parental maize (Prelude) line. During the experiment, the pigs were fed with a grower and a finisher diet both containing 70% maize investigated in a previously study which showed that they contained similar ME values and digestibility of crude nutrients. The pigs with an initial live weight of 23.9 +/- 3.0 kg were allotted to single boxes. During a 91 days growing period the pigs of both groups recorded equal performance in daily weight gain (AW) 815 +/- 93 vs. 804 +/- 64 g/d depending on equal amounts of feed intake 1.95 +/- 0.15 vs. 1.94 +/- 0.15 kg/d (parental vs. transgenic). The results confirm equal performance among growing-finishing pigs fed parental or genetically modified maize containing diets. For slaughtering the pigs were divided into 4 groups with a different duration of the finishing period. After slaughtering the carcass characteristic were registered.

Investigations on genetically modified maize (Bt-maize) in pig nutrition: chemical composition and nutritional evaluation

The objective of the present study was to determine the composition and the nutritional value of parental and transgenic maize seeds fed to pigs. The parental maize line was genetically modified to incorporate a gene from Bacillus thuringiensis (Bt) expressing a toxin against the European corn borer (Ostrinia nubilalis). Both (parental and transgenic) maize lines were analyzed for crude nutrients, starch, sugar, non-starch polysaccharides (NSP), amino acids, fatty acids, as well as for selected minerals. Furthermore, four complete diets were mixed and were analyzed for the same nutrients and some selected ingredients. The diets contained 70% maize to attain a high effect level. To evaluate the feeding value of one variety of genetically modified maize (transgenic) compared to the feeding value of the unmodified maize (parental) line, a balance study with twelve pigs was designed. Three collecting periods were used for each maize line each with six animals. The collected faeces were analyzed for crude nutrients. All measured parameters were virtually the same (e.g. crude protein 11.59% vs. 11.06% in DM), especially the digestibility of crude protein (85.8 +/- 2.3% vs. 86.1 +/- 1.8%), the amount of nitrogen-free-extract (92.8 +/- 0.6% vs. 93.2 +/- 0.6%) and the metabolizable energy (15.7 +/- 0.2% vs. 15.8 +/- 0.2% MJ/kg DM) for both maize lines. Compared to the parental line, the chemical composition and digestibility of crude nutrients and energy content were not significantly affected by the genetic modification of maize. Therefore, from the view of a nutritional assessment, the genetically modified maize can be regarded as substantially equivalent to the parental maize line.

Lipoastrocytoma: a rare low-grade astrocytoma variant of pediatric age

We report on two children with cerebral gliomas showing extensive lipomatous change of tumor cells. One tumor was a large mass occupying the temporal and occipital lobes of the left hemisphere; the other was a cystic lesion with a mural nodule in the left frontal lobe. Histologically, both tumors were composed of glial cells that contained fat droplets coalescing into a single large droplet, thus resulting in an appearance similar to adipocytes. Immunohistochemistry showed GFAP positivity of tumor cells, which was maintained in the cytoplasmic rim of lipidized cells. Synaptophysin and neurofilaments were negative. Ki-67/Mib1 labeling index was low. Electron microscopy showed intracytoplasmic lipid vacuoles, abundant intermediate filaments and a basal lamina surrounding the cell bodies. Molecular genetic analysis of one tumor revealed no TP53 mutation (exons 4-10), no loss of CDKN2A, and no amplification of EGFR, CDK4 or MDM2. Both patients are alive and well after 3 and 7 years, respectively. However, one of them had to be re-operated on circumscribed local recurrences. Our cases represent a rare variant of low-grade astrocytoma that may be designated as "lipoastrocytoma".

Sulfonylurea drugs do not influence initial stroke severity and in-hospital outcome in stroke patients with diabetes

BACKGROUND AND PURPOSE

Sulfonylurea drugs inhibit ATP-dependent potassium channels and may increase mortality after myocardial infarction. Sulfonylurea drugs also inhibit ischemic preconditioning in experimental models of brain ischemia and in clinical studies in the human heart.

METHODS

In the present study we examined the impact of sulfonylurea drugs on in-hospital mortality and the immediate neurological deficit of diabetic stroke patients. From a larger stroke data bank, we studied 146 diabetic patients with acute hemispheric ischemic stroke. Sixty patients were using sulfonylurea drugs.

RESULTS

Major baseline characteristics such as age, blood pressure, admission glucose level, HbA(1c), distribution of cardiovascular risk factors, and presumed stroke etiology (Trial of Org 10172 in Acute Stroke Treatment [TOAST] criteria) were not different. Mortality (15% versus 14%; P=0.86) and initial stroke severity (Canadian Neurological Scale score, 7.4 versus 7.5; P=0.79) were not significantly different between patients with and without sulfonylurea drugs. Further end points such as Rankin Scale score, deteriorating stroke, duration of hospital stay, type of infarcts on CT/MRI, requirement of intensive care, and complications were not different. In a stepwise logistic regression model, sulfonylurea drugs were not independent predictors for increased mortality, deteriorating stroke, or stroke severity.

CONCLUSIONS

In the present hospital-based study, sulfonylurea drugs in patients with diabetes and stroke are not associated with increased stroke severity, mortality, or a worse in-hospital outcome.

Foci on fanconi

The protein network protecting the stability of the genome is defective in Fanconi anemia (FA). The newest in a series of FA proteins is involved in DNA damage response, but the mechanism is still unclear. Clues may come from yeast two-hybrid experiments, an extraordinarily successful tool for determining molecular function.

Modeling whale audiograms: effects of bone mass on high-frequency hearing

In a previous paper (Hemilä et al., Hear. Res. 133 (1999) 82-97) we have presented a mechanical model, based on species-specific anatomical data, for the toothed whale middle ear. For five odontocete species of six we found that the model quite well predicted published behavioral audiograms. Here we report that new published data indicate that the audiogram of the sixth and deviating species, the killer whale Orcinus orca, was from a specimen with deficient high-frequency hearing. A new published killer whale audiogram is similar to other odontocete audiograms and does fit our four-bone model. With certain general conditions, a model with isometric (middle) ears results in uniform audiograms for different species, when presented in a log-log plot; with larger ears the audiogram curves are just moved towards lower frequencies. The audiograms coincide in case all frequencies are scaled by a factor 1/m3, where m is the mass of the ear ossicles. Odontocete ears are isometric enough to show that the corresponding audiograms are indeed similar after such mass scaling. Specifically, this scaling factor can be used to predict the high-frequency hearing limits of all odontocete species. Our anatomical data and models support the notion that ossicular mass is a crucial factor limiting high-frequency hearing in both terrestrial mammals and toothed whales.

In search of the visual pigment template

Absorbance spectra were recorded by microspectrophotometry from 39 different rod and cone types representing amphibians. reptiles, and fishes, with A1- or A2-based visual pigments and lambdamax ranging from 357 to 620 nm. The purpose was to investigate accuracy limits of putative universal templates for visual pigment absorbance spectra, and if possible to amend the templates to overcome the limitations. It was found that (1) the absorbance spectrum of frog rhodopsin extract very precisely parallels that of rod outer segments from the same individual, with only a slight hypsochromic shift in lambdamax, hence templates based on extracts are valid for absorbance in situ: (2) a template based on the bovine rhodopsin extract data of Partridge and De Grip (1991) describes the absorbance of amphibian rod outer segments excellently, contrary to recent electrophysiological results; (3) the lambdamax/lambda invariance of spectral shape fails for A1 pigments with small lambdamax and for A2 pigments with large lambdamax, but the deviations are systematic and can be readily incorporated into, for example, the Lamb (1995) template. We thus propose modified templates for the main "alpha-band" of A1 and A2 pigments and show that these describe both absorbance and spectral sensitivities of photoreceptors over the whole range of lambdamax. Subtraction of the alpha-band from the full absorbance spectrum leaves a "beta-band" described by a lambdamax-dependent Gaussian. We conclude that the idea of universal templates (one for A1- and one for A2-based visual pigments) remains valid and useful at the present level of accuracy of data on photoreceptor absorbance and sensitivity. The sum of our expressions for the alpha- and beta-band gives a good description for visual pigment spectra with lambdamax > 350 nm.

Strong FANCA/FANCG but weak FANCA/FANCC interaction in the yeast 2-hybrid system

Three of at least 8 Fanconi anemia (FA) genes have been cloned (FANCA, FANCC, FANCG), but their functions remain unknown. Using the yeast 2-hybrid system and full-length cDNA, the authors found a strong interaction between FANCA and FANCG proteins. They also obtained evidence for a weak interaction between FANCA and FANCC. Neither FANCA nor FANCC was found to interact with itself. These results support the notion of a functional association between the FA gene products. (Blood. 2000;95:719-720)

A model of the odontocete middle ear

The high acoustic sensitivity of the bottlenose dolphin is physically defined and related to the anatomy of the middle ear. The paper presents a conceptual and parametric analysis of the demands imposed by this high sensitivity upon the middle ear mechanisms: the head and the middle ear structures must collect sound energy from a large area and concentrate it onto the oval window. Assuming that the specific input impedance of the mammalian cochlea is relatively constant, and smaller than the characteristic acoustic impedance of water, we find that the impedance matching task of the cetacean middle ear is very different from that of terrestrial mammals: instead of a large pressure amplification, cetaceans need amplification of particle velocity. Our mechanical four-bone model of the odontocete middle ear is based on the anatomy of the tympano-periotic complex and consists of four rigid bone units (tympanic bone, the malleus-incus complex, stapes, periotic bone) connected through elastic junctions. The velocity amplification is brought about by lever mechanisms and elastic couplings. The model produced velocity amplifications ranging from 7- to 23-fold when provided with middle ear parameters from the six odontocete species for which audiograms are available. The model reproduces the complete audiograms of these six species fairly well for frequencies up to about 100-120 kHz.

Scaling of the cetacean middle ear

Functionally interesting dimensions of the tympano-periotic complex were measured and compared in 18 odontocete and six mysticete species, ranging from small porpoises to the blue whale. We determined (i) the masses of the tympanic and periotic bones (T and P) and of the ossicles malleus, incus, and stapes (M, I and S), (ii) the volume occupied bythe tympanic bone (V), (iii) the areas of the tympanic plate and oval window (A1 and A2), (iv) the thickness of the tympanic plate (D), and (v) the densities of the ossicles (dM, dI, and dS). In most cases, roughly isometric scaling was found in both toothed and baleen whales. P is isometric to T, and the tympanic bone is structurally isometric in all species studied, although not within mysticetes as a group, shown by the isometric relations of V to T, of T(2/3) to A1, and of D to square root(A1). The essentially isometric scaling of the tympanic bone provides a basis for the functional models described by Hemilä et al. (1999). The relation of S to M+I is also isometric, but the relation of M+I+S to T is negatively allometric, as is the relation of A2 to A1, both with slopes close to 2/3. The possible functional implication of this allometry is unknown. The mean ossicular density is 2.64 g/cm3 for odontocetes, and 2.35 g/cm3 for mysticetes. The highly mineralized and convex tympanic plate provides cetaceans with a uniquely large and stiff sound collecting area.

The anatomy of the killer whale middle ear (Orcinus orca)

The paper first reviews our present understanding of the functional morphology of the odontocete (toothed whale) ear. The tympano-periotic complex forming the ear region consists of a ventral bowl-shaped tympanic bone in direct contact with the surrounding soft tissues and the incident sound, and a dorsal periotic bone containing the inner ear. Apparently sound brings the tympanic bone, and especially its thin tympanic plate, into vibration. The ossicles in the air-filled middle ear cavity form a bridge from the tympanic plate to the periotic bone connecting the vibrating plate to the oval window and the inner ear. Our computer tomography (CT) sections and camera lucida drawings reveal two hitherto unknown features of the odontocete ear, both of them of potential relevance to sound reception and impedance matching. (1) It is well known that, in addition to the ossicular chain, two other bone structures connect the tympanic to the periotic bone. We show that the most delicate parts of these extra-ossicular connections consist of thin and folded bony sheets which apparently allow compliance in the tympano-periotic bone contacts and enable plate vibration in relation to the periotic bone. (2) The round head of the malleus, in combination with a fitting round depression on the periotic side, seems to form a joint. We propose that this (hypothetical) joint, together with the adjacent structures, forms a lever producing an amplification of the vibration velocity at the level of the oval window.

Molecular basis of dark adaptation in rod photoreceptors

Following exposure of the eye to an intense light that 'bleaches' a significant fraction of the rhodopsin, one's visual threshold is initially greatly elevated, and takes tens of minutes to recover to normal. The elevation of visual threshold arises from events occurring within the rod photoreceptors, and the underlying molecular basis of these events and of the rod's recovery is now becoming clearer. Results obtained by exposing isolated toad rods to hydroxylamine solution indicate that, following small bleaches, the primary intermediate causing elevation of visual threshold is metarhodopsin II, in its phosphorylated and arrestin-bound form. This product activates transduction with an efficacy about 100 times greater than that of opsin.

Inactivation of viruses by beta-propiolactone in human cryo poor plasma and IgG concentrates

Virus inactivation by cold treatment with beta-propiolactone (BPL) was investigated in human cryo poor plasma and purified IgG concentrates spiked with relevant human viruses or appropriate animal model viruses. The samples were treated with 0.1 or 0.25% BPL for 300 or 480 min, respectively. Residual infectivity was determined by standard microtitration assays on tissue culture cells. The inactivation of all viruses tested was more effective in IgG than in plasma. IgG: R1=4-5.5 log10 for vesicular stomatitis virus (VSV). Semliki Forest virus (SFV), bovine virus diarrhoea virus (BVDV), murine encephalomyelitis virus (MEV), feline calicivirus (FVC), suid parvovirus (PPV), simian virus 40 (SV40); R1=2-4 log10 for suid herpesvirus type 1 (SHV-1), bovine herpesvirus type 1 (BHV-1), human immunodeficiency virus type 2 (HIV-2), simian immunodeficiency virus (SIVagm3). Plasma: R1=3-5 log10 for VSV, SFV, BVDV, SHV-1, MEV:R1=0-3 log10 for HIV-1, SIVagm3 BHV-1, FCV, PPV, SV40. After addition of SIVagm3, HIV-2, and PPV to plasma or IgG, spontaneous inactivation without further addition of BPL was observed. These results demonstrate that treatment with BPL has a limited capacity to inactivate viruses. Different inactivation kinetics were observed in plasma and IgG concentrates. Therefore, virus inactivation by BPL must be tested for individual blood products independently and should not be extrapolated from other model systems.

Rod pigment and rod noise in the European toad Bufo bufo

Behavioural experiments and ganglion cell recordings indicate that the visual sensitivity of dark-adapted toads is limited by the occurrence of spontaneous isomerization-like noise events in the rods. The frequency of these "false photons" has previously been studied (with micropipette recording) in the toad species Bufo marinus, while the behavioural thresholds were determined using Bufo bufo toads. Thus, it was necessary to check that the noise event frequency is roughly the same in these two species. Here we show that it is, in both species, close to 0.02 events per second and rod (at 22 degrees C). Using microspectrophotometry we further show that the absorption spectra of these two rhodopsins are very similar, peaking around 503.3 and 501.8 nm for B. marinus and B. bufo, respectively.

[Immunoblastic highly malignant lymphoma of the uterine cervix]

Report on a case of a highly malignant solitary lymphoma of the cervix uteri in a 51-year-old patient. The only noticeable finding leading to the diagnosis was the pathological result of the routine cervical smear. Solitary malignant lymphomas of the cervix must be seen as systemic diseases. They should therefore be treated by local surgical intervention and consecutive systemical chemotherapy in an interdisciplinary conception.

What middle ear parameters tell about impedance matching and high frequency hearing

Acoustic energy enters the mammalian cochlea aided by an anatomical impedance matching performed by the middle ear. The purpose of this paper is to analyse the functional consequences of changes in scale of the middle ear when going from the smallest mammals to the largest. Our anatomical measurements in mammals of different sizes ranging from bats to elephants indicate that middle ear proportions are largely isometric. Thus the calculated transformer ratio is basically independent of animal size, a typical value lying between 30 and 80. Similarly, the calculated specific acoustic input impedance of the inner ear is independent of animal size, the average value being about 140 kPa s/m. We show that if the high frequency hearing limit of isometric ears is limited by ossicle inertia, it should be inversely proportional to the cubic root of the ossicular mass. This prediction is in reasonable agreement with published audiogram data. We then present a three-parameter model of the middle ear where some obvious deviations from perfect isometry are taken into account. The high frequency hearing limits of different species generally agree well with the predictions of this simple model. However, the hearing limits of small rodents clearly deviate from the model calculation. We interpret this observation as indicating that the hearing limit towards very high frequencies may be set by cochlear transduction mechanisms. Further we discuss the exceptional high frequency hearing of the cat and the amphibious hearing of seals.